Wireguard VPN and accessing internal DNS server

[Bluecube]

I've been using Wireguard to access my home network for years now and it's been great. One bugbear is that to access internal resources I've always had to type in the IP address rather a friendly URL. I know it's a DNS issue but I've idea how to rectify it despite googling and many hours of fiddling. Can anyone point out what I've been missing?

I don't think it makes much difference but I'm currently running Wireguard on a UDM. Previously it was on Unraid. The issue persists across the platforms.

 

[Bluecube]

I'm using a Mac if that makes any difference. Typing in Nslookup returns NXDOMAIN.

Thanks for all the info. Networking is a real weak spot in my IT knowledge and I didn’t realise there were so many different nuances to DNS. I thought I was running a DNS server on either my UDM or Adblock server but these don’t resolve local DNS names from what I can see and experience. I’ll look into this further but I think I need a ”proper” DNS server to resolve local addresses to hostnames and point WireGuard at it.