I am using custom adblock hosts files as well as dns query logging to a separate file (logfacility property). The crash was due to the latter. ujail needs to know about the logfacility file and allow dnsmasq to write to it. A patched dnsmasq init script will fix this.
Other than that, working fine now on both TPLink Archer A7v5 and Netgear 6700v2.
Thanks, but unfortunately this does not solve the problem for me. The modules kmod-nf-reject6 and kmod-nf-conntrack6 were already installed by default and the module kmod-nf-ipt6 or kmod-nf-ipt did not help, but seems to be for the no longer used iptables anyway. Too bad on my other router everything works fine.
Trying out 22.03.0-rc1 on my Archer C7 v2 I found that IPv6 from LAN to WAN and vice versa works fine, but not Pv4. IPv4 on the subnet and to the router works fine and IPv4 from the router to the internet also works fine, but something seems wrong with the transmission of IPv4 packets from LAN to WAN and vice versa. Switched back to 21.02.3, now everything works as expected again. On my other router (gl.inet) version 22.03.0-rc1 works fine, strange.