Question about in-app DNS settings

[terminal-cs]

I see these two settings in the app's settings menu called VPN DNS, does the app first filter all the traffic normally, and then send traffic though the DNS set in the apps settings? It's not very clear in the app itself, and if it does, does it work just like the private DNS feature in Android? If not, you should definitely add that since it's not possible to use the app filtering and private DNS at the same time.