No luck editing the AllowedIPs to either to @binhex listed subnet mask (10.0.0.0/8 let me access locally but blocked DNS resolution for torrents inside the container) should I try something else? I don't seem to have the wg0.conf overwrite problem, have you tried locking down the permissions on the file to read only?
Just to second @weirdcrap here I also have this problem accessing my web ui with a Wireguard VPN active, no matter what I list under LAN_NETWORK. Reverse Proxy and access from other containers (sonarr, radarr etc) works though, just direct IP access fails to resolve.