Wireguard & NexDNS

Yes it is called Tailscale which is built upon Wireguard. 

Use Tailscale as a mesh-based VPN for your devices. Assign one device as your Tailscale exit node. Run the NextDNS CLI on that device.

Any device running Tailscale can, if enabled, route their traffic out (encrypted via Wireguard) via the device assigned as an exit node. Since that exit node is running NextDNS you can have all of the DNS requests going out under the DOH configuration for that exit node.

Wireguard VPN + NextDNS  :-)

Typical setup would be a VPS as the exit node.

Even I am trying to figure out how to use NextDNS with Wireguard. For me I am trying to use Windscribe through Wireguard. 

I couldn't find how it works with Wireguard or OpenVPN. But it works great with AdGuard VPN for your iOS device. With any DNS protocol.. DoH, DoT or DoQ..

I found different ways to make it work. On iOS, run the NextDNS profile as instructed. Import your Wireguard profile to the Wireguard app, then delete the default DNS servers in the Wireguard  profile and connect. Now you have the VPN‘s IP address and NextDNS over https. For both MacOS and iOS you can also use the Passepartout app. It’s a one time purchase but then you can import Wireguard profiles and change DNS settings to fit your choice.