WireGuard VPN from tutorial not resolving DNS of Wireguard server. How to debug dns leaks?

I have followed your @LinuxBabe wireguard tutorial to the tee, and as of a month ago, had the wireguard client fully working and resolving its IP address and DNS address to the VPN server properly. After some updates or an unknown change that I made, My VPN Client no longer resolves to the VPN’s dns servers, but instead, resolves to my local dns servers on my router. Can someone recommend a way to start debugging dns leaks? I need to figure out what exactly I have done wrong, or if an upgrade broke my dns resolver on the client, and I have no idea where to start debugging this. Any help is very much appreciated!