After using WireGuard to VPN into my LAN, I can use RDP or SSH+VNC to control machines on my LAN. I am able to reach them via IP or by host.domain.private for remote control, but I cannot browse to
\\host.domain.private\share for the same machine to access its network share.
I prefer using a different IP pool than my LAN, otherwise you can run into routing issues (same IP on 2 segments).
If using the Wireguard IP doesn’t work, then something is blocking SMB specifically (from memory that’s UDP 137,138 and TCP 137,139, 445. Double check that).
I don’t use Wireguard directly, but Tailscale, which uses Wireguard, and I’d have to specifically block those.
Try doing a trace (tracert on Windows) of the destination address (in both directions) to see where traffic goes.
On Linux you can traceroute the SMB ports, on Windows nmap.exe can effectively do the same thing.