I use IPV6-PD to assign an IPV6 address to my LAN device. How do I configure a firewall? And how to enable RFC4941 and RFC7217 on the WAN port?

If you are worried about IPv6 privacy on your router addressing, see:

There's a method to enable random IPs on the router. You router's IPv6 address will change on each reboot or up/down. Be sure to generate your own secret - do not use the secret generated in the posting!