- Open the GUI network settings
- Set DNS to the IP of the PiHole, make sure the “automatic” switch is off.
- Do the above for each active interface (ethernet, wlan) and for both IPv4 and IPv6
- Save/apply settings
- Turn the interface(s) off, then back on
resolvectl flush-caches
just in case
Look at resolvectl dns
to check there’s no DHCP-acquired DNS servers set anymore
If you use a VPN, those often set their own DNS servers too, remember to check it as well.
Imagine if all the people who prefer systemd would write posts like this as often as the opposition. Just use what you like, there are plenty of distros to choose from.