maybe this guides can help you getting started:https://homenetworkguy.com/how-to/set-up-a-fully-functioning-home-network-using-opnsense/or ipv6 only: https://homenetworkguy.com/how-to/configure-ipv6-opnsense-with-isp-such-as-comcast-xfinity/his tutorials have helpt me also in the beginning to get things started.
You cannot delegate a /64 to your LAN, though what you need is NAT for IPv6 using ULAs in LAN (and other interfaces if needed).Please provide screenshots of you intefaces overview first.Then you need to enable manual configuration for LAN interface, go to services/router advertisements and select assisted mode for LAN. Next go to interfaces/virtual IPs and add ULA address for LAN interface, e.g. fd00:10:10:10::1/64.Then go to firewall/NAT/outbound and select hybrid mode. Add a manual rule with interface = WG network, IP version = v6, source address = fd00:10:10::/64Make sure your LAN clients gets v6 addresses via SLAAC, e.g. fd00:10:10:10:1234:abcd:a1b2:e3f6I guess this should work, I only do so for my VPN client networks to give them v6 connectivity without delegeting GUAs (since this is not really static in my case).
you need to enable manual configuration for LAN interface,
The do it all for "User" interface
It is in Interface config, not services...