Self-hosting be like ^^
I think I had issues similar to that. Perhaps the PiHole is running a conflicting DHCP server? I have my own set of weird issues.. Bad connectivity so I need a WiFi range extender, but it's not a true extender and has its own IP address, acting as a router sometimes and not forwarding DNS queries to the main router.. That, a lack of NAT loopback functionality, a lack of changeable DNS settings and the AdGuard Home apparently taking precedent in that side of the house, and I have a cocktail of connection issue bs lol. The main router can DNS perfectly fine, but if I'm connected to the extender I have to add DNS rewrites to AGH.. which works for most services..
The journey is largely about overcoming obstacles aha, and the reward for doing so.. Hope yours goes well!