Unable to establish IPv6 WAN->LAN connections

Hi,
I am trying to get inbound IPv6 http(s) connections forwarded to server in LAN.
Firewall log does not report rejected connections when I try to access server on correct (according to rules) port. When I try to use incorrect port, I get rejection report in log.
Using correct port also increments counters at matching nftables rule.
When I try to connect to server from LAN, everything works.
My assumption is, that firewall accepts connection, but something else is broken.

I am quite new in IPv6 world.

config dump (nw, fw, dhcp)
(MACs and static IP assignments are redacted)

network.loopback=interface
network.loopback.device='lo'
network.loopback.proto='static'
network.loopback.ipaddr='127.0.0.1'
network.loopback.netmask='255.0.0.0'
network.globals=globals
network.globals.ula_prefix='fdd6:4ff4:6ca9::/48'
network.@device[0]=device
network.@device[0].name='br-lan'
network.@device[0].type='bridge'
network.@device[0].ports='lan1' 'lan2' 'lan3' 'lan4'
network.lan=interface
network.lan.device='br-lan'
network.lan.proto='static'
network.lan.ip6assign='60'
network.lan.ipaddr='10.0.0.1'
network.lan.netmask='255.255.0.0'
network.wan=interface
network.wan.proto='pppoe'
network.wan.device='wan.848'
network.wan.username='O2'
network.wan.password='O2'
network.wan.ip6assign='64'
network.wan.ipv6='auto'
network.@device[1]=device
network.@device[1].type='8021q'
network.@device[1].ifname='wan'
network.@device[1].vid='848'
network.@device[1].name='wan.848'

firewall.@defaults[0]=defaults
firewall.@defaults[0].input='ACCEPT'
firewall.@defaults[0].output='ACCEPT'
firewall.@defaults[0].forward='REJECT'
firewall.@defaults[0].synflood_protect='1'
firewall.@defaults[0].flow_offloading='1'
firewall.@zone[0]=zone
firewall.@zone[0].name='lan'
firewall.@zone[0].input='ACCEPT'
firewall.@zone[0].output='ACCEPT'
firewall.@zone[0].forward='ACCEPT'
firewall.@zone[0].network='lan'
firewall.@zone[1]=zone
firewall.@zone[1].name='wan'
firewall.@zone[1].input='REJECT'
firewall.@zone[1].output='ACCEPT'
firewall.@zone[1].forward='REJECT'
firewall.@zone[1].masq='1'
firewall.@zone[1].mtu_fix='1'
firewall.@zone[1].log='1'
firewall.@zone[1].network='wan'
firewall.@forwarding[0]=forwarding
firewall.@forwarding[0].src='lan'
firewall.@forwarding[0].dest='wan'
firewall.@rule[0]=rule
firewall.@rule[0].name='Allow-DHCP-Renew'
firewall.@rule[0].src='wan'
firewall.@rule[0].proto='udp'
firewall.@rule[0].dest_port='68'
firewall.@rule[0].target='ACCEPT'
firewall.@rule[0].family='ipv4'
firewall.@rule[1]=rule
firewall.@rule[1].name='Allow-Ping'
firewall.@rule[1].src='wan'
firewall.@rule[1].proto='icmp'
firewall.@rule[1].icmp_type='echo-request'
firewall.@rule[1].family='ipv4'
firewall.@rule[1].target='ACCEPT'
firewall.@rule[2]=rule
firewall.@rule[2].name='Allow-IGMP'
firewall.@rule[2].src='wan'
firewall.@rule[2].proto='igmp'
firewall.@rule[2].family='ipv4'
firewall.@rule[2].target='ACCEPT'
firewall.@rule[3]=rule
firewall.@rule[3].name='Allow-DHCPv6'
firewall.@rule[3].src='wan'
firewall.@rule[3].proto='udp'
firewall.@rule[3].dest_port='546'
firewall.@rule[3].family='ipv6'
firewall.@rule[3].target='ACCEPT'
firewall.@rule[4]=rule
firewall.@rule[4].name='Allow-MLD'
firewall.@rule[4].src='wan'
firewall.@rule[4].proto='icmp'
firewall.@rule[4].src_ip='fe80::/10'
firewall.@rule[4].icmp_type='130/0' '131/0' '132/0' '143/0'
firewall.@rule[4].family='ipv6'
firewall.@rule[4].target='ACCEPT'
firewall.@rule[5]=rule
firewall.@rule[5].name='Allow-ICMPv6-Input'
firewall.@rule[5].src='wan'
firewall.@rule[5].proto='icmp'
firewall.@rule[5].icmp_type='echo-request' 'echo-reply' 'destination-unreachable' 'packet-too-big' 'time-exceeded' 'bad-header' 'unknown-header-type' 'router-solicitation' 'neighbour-solicitation' 'router-advertisement' 'neighbour-advertisement'
firewall.@rule[5].limit='1000/sec'
firewall.@rule[5].family='ipv6'
firewall.@rule[5].target='ACCEPT'
firewall.@rule[6]=rule
firewall.@rule[6].name='Allow-ICMPv6-Forward'
firewall.@rule[6].src='wan'
firewall.@rule[6].dest='*'
firewall.@rule[6].proto='icmp'
firewall.@rule[6].icmp_type='echo-request' 'echo-reply' 'destination-unreachable' 'packet-too-big' 'time-exceeded' 'bad-header' 'unknown-header-type'
firewall.@rule[6].limit='1000/sec'
firewall.@rule[6].family='ipv6'
firewall.@rule[6].target='ACCEPT'
firewall.@rule[7]=rule
firewall.@rule[7].name='Allow-IPSec-ESP'
firewall.@rule[7].src='wan'
firewall.@rule[7].dest='lan'
firewall.@rule[7].proto='esp'
firewall.@rule[7].target='ACCEPT'
firewall.@rule[8]=rule
firewall.@rule[8].name='Allow-ISAKMP'
firewall.@rule[8].src='wan'
firewall.@rule[8].dest='lan'
firewall.@rule[8].dest_port='500'
firewall.@rule[8].proto='udp'
firewall.@rule[8].target='ACCEPT'
firewall.@rule[9]=rule
firewall.@rule[9].family='ipv6'
firewall.@rule[9].src='wan'
firewall.@rule[9].dest='lan'
firewall.@rule[9].dest_ip='2001:db8:ffff:ffff::3e5'
firewall.@rule[9].target='ACCEPT'
firewall.@rule[9].proto='tcp'
firewall.@rule[9].name='to NAS'
firewall.@rule[9].dest_port='443 80 12121'

dhcp.@dnsmasq[0]=dnsmasq
dhcp.@dnsmasq[0].domainneeded='1'
dhcp.@dnsmasq[0].localise_queries='1'
dhcp.@dnsmasq[0].rebind_protection='1'
dhcp.@dnsmasq[0].rebind_localhost='1'
dhcp.@dnsmasq[0].local='/lan/'
dhcp.@dnsmasq[0].domain='lan'
dhcp.@dnsmasq[0].expandhosts='1'
dhcp.@dnsmasq[0].authoritative='1'
dhcp.@dnsmasq[0].readethers='1'
dhcp.@dnsmasq[0].leasefile='/tmp/dhcp.leases'
dhcp.@dnsmasq[0].resolvfile='/tmp/resolv.conf.d/resolv.conf.auto'
dhcp.@dnsmasq[0].localservice='1'
dhcp.@dnsmasq[0].ednspacket_max='1232'
dhcp.lan=dhcp
dhcp.lan.interface='lan'
dhcp.lan.start='100'
dhcp.lan.limit='150'
dhcp.lan.leasetime='12h'
dhcp.lan.dhcpv4='server'
dhcp.lan.dhcpv6='server'
dhcp.lan.ra='server'
dhcp.lan.ra_flags='managed-config' 'other-config'
dhcp.wan=dhcp
dhcp.wan.interface='wan'
dhcp.wan.ignore='1'
dhcp.odhcpd=odhcpd
dhcp.odhcpd.maindhcp='0'
dhcp.odhcpd.leasefile='/tmp/hosts/odhcpd'
dhcp.odhcpd.leasetrigger='/usr/sbin/odhcpd-update'
dhcp.odhcpd.loglevel='4'
dhcp.@host[0]=host
dhcp.@host[0].name='paranoia'
dhcp.@host[0].dns='1'
dhcp.@host[0].mac='18:C0:4D:11:22:33'
dhcp.@host[0].ip='10.0.0.10'
dhcp.@host[0].hostid='3e5'
dhcp.@host[0].duid='0004b1b1ae94522da636f1a36a7f5104cefd'
dhcp.@host[1]=host
dhcp.@host[1].name='dgtsnb'
dhcp.@host[1].dns='1'
dhcp.@host[1].mac='60:67:20:44:55:66'
dhcp.@host[1].ip='10.0.0.196'
dhcp.@host[1].duid='00041d1bf1ea2fd11ab71fc53e5bae93327b'
dhcp.@host[1].hostid='dddd'

nftables rules

table inet fw4 {
	flowtable ft {
		hook ingress priority filter
		devices = { lan1, lan2, lan3, lan4, pppoe-wan, wan, wlan0, wlan1 }
	}

	chain input {
		type filter hook input priority filter; policy accept;
		iifname "lo" accept comment "!fw4: Accept traffic from loopback"
		ct state established,related accept comment "!fw4: Allow inbound established and related flows"
		tcp flags syn / fin,syn,rst,ack jump syn_flood comment "!fw4: Rate limit TCP syn packets"
		iifname "br-lan" jump input_lan comment "!fw4: Handle lan IPv4/IPv6 input traffic"
		iifname "pppoe-wan" jump input_wan comment "!fw4: Handle wan IPv4/IPv6 input traffic"
	}

	chain forward {
		type filter hook forward priority filter; policy drop;
		meta l4proto { tcp, udp } flow add @ft
		ct state established,related accept comment "!fw4: Allow forwarded established and related flows"
		iifname "br-lan" jump forward_lan comment "!fw4: Handle lan IPv4/IPv6 forward traffic"
		iifname "pppoe-wan" jump forward_wan comment "!fw4: Handle wan IPv4/IPv6 forward traffic"
		jump handle_reject
	}

	chain output {
		type filter hook output priority filter; policy accept;
		oifname "lo" accept comment "!fw4: Accept traffic towards loopback"
		ct state established,related accept comment "!fw4: Allow outbound established and related flows"
		oifname "br-lan" jump output_lan comment "!fw4: Handle lan IPv4/IPv6 output traffic"
		oifname "pppoe-wan" jump output_wan comment "!fw4: Handle wan IPv4/IPv6 output traffic"
	}

	chain prerouting {
		type filter hook prerouting priority filter; policy accept;
		iifname "br-lan" jump helper_lan comment "!fw4: Handle lan IPv4/IPv6 helper assignment"
	}

	chain handle_reject {
		meta l4proto tcp reject with tcp reset comment "!fw4: Reject TCP traffic"
		reject comment "!fw4: Reject any other traffic"
	}

	chain syn_flood {
		limit rate 25/second burst 50 packets return comment "!fw4: Accept SYN packets below rate-limit"
		drop comment "!fw4: Drop excess packets"
	}

	chain input_lan {
		jump accept_from_lan
	}

	chain output_lan {
		jump accept_to_lan
	}

	chain forward_lan {
		jump accept_to_wan comment "!fw4: Accept lan to wan forwarding"
		jump accept_to_lan
	}

	chain helper_lan {
	}

	chain accept_from_lan {
		iifname "br-lan" counter packets 3 bytes 228 accept comment "!fw4: accept lan IPv4/IPv6 traffic"
	}

	chain accept_to_lan {
		oifname "br-lan" counter packets 0 bytes 0 accept comment "!fw4: accept lan IPv4/IPv6 traffic"
	}

	chain input_wan {
		meta nfproto ipv4 udp dport 68 counter packets 0 bytes 0 accept comment "!fw4: Allow-DHCP-Renew"
		icmp type echo-request counter packets 0 bytes 0 accept comment "!fw4: Allow-Ping"
		meta nfproto ipv4 meta l4proto igmp counter packets 0 bytes 0 accept comment "!fw4: Allow-IGMP"
		meta nfproto ipv6 udp dport 546 counter packets 0 bytes 0 accept comment "!fw4: Allow-DHCPv6"
		ip6 saddr fe80::/10 icmpv6 type . icmpv6 code { mld-listener-query . no-route, mld-listener-report . no-route, mld-listener-done . no-route, mld2-listener-report . no-route } counter packets 0 bytes 0 accept comment "!fw4: Allow-MLD"
		icmpv6 type { destination-unreachable, time-exceeded, echo-request, echo-reply, nd-router-solicit, nd-router-advert } limit rate 1000/second counter packets 0 bytes 0 accept comment "!fw4: Allow-ICMPv6-Input"
		icmpv6 type . icmpv6 code { packet-too-big . no-route, parameter-problem . no-route, nd-neighbor-solicit . no-route, nd-neighbor-advert . no-route, parameter-problem . admin-prohibited } limit rate 1000/second counter packets 0 bytes 0 accept comment "!fw4: Allow-ICMPv6-Input"
		jump reject_from_wan
	}

	chain output_wan {
		jump accept_to_wan
	}

	chain forward_wan {
		icmpv6 type { destination-unreachable, time-exceeded, echo-request, echo-reply } limit rate 1000/second counter packets 0 bytes 0 accept comment "!fw4: Allow-ICMPv6-Forward"
		icmpv6 type . icmpv6 code { packet-too-big . no-route, parameter-problem . no-route, parameter-problem . admin-prohibited } limit rate 1000/second counter packets 0 bytes 0 accept comment "!fw4: Allow-ICMPv6-Forward"
		meta l4proto esp counter packets 0 bytes 0 jump accept_to_lan comment "!fw4: Allow-IPSec-ESP"
		udp dport 500 counter packets 0 bytes 0 jump accept_to_lan comment "!fw4: Allow-ISAKMP"
		ip6 daddr 2001:db8:ffff:ffff::3e5 tcp dport { 80, 443, 12121 } counter packets 0 bytes 0 jump accept_to_lan comment "!fw4: to paranoia"
		jump reject_to_wan
		log prefix "reject wan forward: "
	}

	chain accept_to_wan {
		oifname "pppoe-wan" counter packets 0 bytes 0 accept comment "!fw4: accept wan IPv4/IPv6 traffic"
	}

	chain reject_from_wan {
		iifname "pppoe-wan" counter packets 0 bytes 0 log prefix "reject wan in: " jump handle_reject comment "!fw4: reject wan IPv4/IPv6 traffic"
	}

	chain reject_to_wan {
		oifname "pppoe-wan" counter packets 0 bytes 0 log prefix "reject wan out: " jump handle_reject comment "!fw4: reject wan IPv4/IPv6 traffic"
	}

	chain dstnat {
		type nat hook prerouting priority dstnat; policy accept;
	}

	chain srcnat {
		type nat hook postrouting priority srcnat; policy accept;
		oifname "pppoe-wan" jump srcnat_wan comment "!fw4: Handle wan IPv4/IPv6 srcnat traffic"
	}

	chain srcnat_wan {
		meta nfproto ipv4 masquerade comment "!fw4: Masquerade IPv4 wan traffic"
	}

	chain raw_prerouting {
		type filter hook prerouting priority raw; policy accept;
	}

	chain raw_output {
		type filter hook output priority raw; policy accept;
	}

	chain mangle_prerouting {
		type filter hook prerouting priority mangle; policy accept;
	}

	chain mangle_postrouting {
		type filter hook postrouting priority mangle; policy accept;
	}

	chain mangle_input {
		type filter hook input priority mangle; policy accept;
	}

	chain mangle_output {
		type route hook output priority mangle; policy accept;
	}

	chain mangle_forward {
		type filter hook forward priority mangle; policy accept;
		iifname "pppoe-wan" tcp flags syn tcp option maxseg size set rt mtu comment "!fw4: Zone wan IPv4/IPv6 ingress MTU fixing"
		oifname "pppoe-wan" tcp flags syn tcp option maxseg size set rt mtu comment "!fw4: Zone wan IPv4/IPv6 egress MTU fixing"
	}
}

Just to be sure, 2001:db8 is not the prefix you are using on wan?

No, I have valid /64 prefix from my ISP. I just replaced it by 2001:db8:ffff:ffff here thus my note

(MACs and static IP assignments are redacted)

K fine, just wanted to make sure.
On a glimpse at least the rule looks correct.
You are able to ping (icmpv6) from wan to lan?
And you do not have any firewall rules on the host rejecting packets from outside the lan?

You are able to ping (icmpv6) from wan to lan?

Nope, I am not able to ping ipv6 LAN device from outside.

And you do not have any firewall rules on the host rejecting packets from outside the lan?

I am not sure if by "host" you mean my server i LAN, which I am trying to reach. If so, it accepts IPv6 connections from others in LAN without issue. There is not any other firewall running on that device.

I tried to stop http server on that device and just listen on port 80/443 with socat with same results as http server. I have also same results with different device in LAN.

May or may not be related, but I can see Virtual dynamic interface (DHCPv6 client) interface in luci, should I do something about that?