DNS doesn't work for machines in lan while wireguard works fine

[deHakkelaar]

Check that line doesnt return after a reboot!
Post results for below ones run on Pi-hole , and on one of your clients in a cmd prompt (Windows/Linux/MacOS):

nslookup pi.hole

nslookup pi.hole 192.168.1.12

EDIT: ow and check if your router doesnt have some kind fo rebind protection or similar:

Why won't Pi-hole work with DNS rebind protection enabled?

What is DNS rebind protection? If your router has an option called DNS rebind protection enabled, you may run into issues when trying to use Pi-hole as your DNS server. The reasons for this are quite technical, but to summarize what this option does in one sentence: DNS rebind protection does not allow DNS queries to be answered with a local IP address. Why does this interfere with Pi-hole? DNS rebind is meant to be a countermeasure to an attack on your network. So in many cases, it's actu…

EDIT2: also check if firewall is blocking on Pi-hole:

pi@ph5:~ $ sudo iptables -nL
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination