NextDNS app or native support?
The answer depends on the platform.
On iOS/iPad, our app is leveraging the native DoH support, so it does not make a difference except you have an easy access to on/off toggle and a simple UI to exclude WiFi networks.
On Android, we use a VPN trick to provide DoH as this platform does not support it natively. If your network does not block DoT you can use the native "Private DNS" feature which will have less issues with other VPN and probably lower battery impact (not proven though).
https://help.nextdns.io/t/83h1vla