I have a WireGuard tunnel between my router and a server on the Internet. Either can establish a connection to the other using their GUAs, and the 172.16.0.0/24 range is used inside the tunnel. The server is also aware of RFC1918 subnets behind the router as they're listed in its AllowedIps conf, and clients can connect to the server at 172.16.0.2.
I'd like to start using IPv6 inside the tunnel as well, but I'm not sure exactly how. I can assign both the router and server a ULA to use in the tunnel which allows them to communicate over IPv6, but clients aren't able to reach the server's ULA because the GUA prefix they connect from isn't in AllowedIps on the server. If I add the clients' GUA prefix to the server's AllowedIps conf they can reach the server's ULA, but not its GUA.
I guess I'd have to advertise the ULA prefix at home, but I'm not sure if that's the best approach. What's everyone else doing?