WireGuard installed to server, using NextDNS with UDP. How to use DOH?

Hello,

I installed wireguard to my linux server. Using it as VPN.
Server is using NextDNS successfully.
But it is using UDP protocol instead of DOH or DOT.

How can I change it from UDP to DOH?

Without VPN everything works with DOH. But when I use VPN connection with this setup, it shows UDP Protocol.

Thank you.