[Feature Request] Allow per-network DNS settings

[thislooksfun]

I have a few local devices on my network that I connect to via local domain names managed by a pi-hole instance. I'd like to keep using that setup while still getting the benefits of having a VPN for the rest of my traffic. The issue is that if I configure the iOS app to use a custom DNS server pointing at my pi-hole then everything works just fine... right up until I leave the house, at which point it can no longer connect to my pi-hole. And even worse, if I then connect to another network my phone will try to connect to the device there, which could end up being insecure.

I could get around this with adding a second DNS server (i.e. Quad9), but I'm under the impression that DNS requests will round-robin through the listed servers, not use them as a failover. Plus it still has the other-network IP collision issue mentioned above.

My ideal solution is two parts:

1. Expand the Automation system to allow configuring DNS settings on a per-network-connection basis.
2. (optional, but would make it more seamless) add more options to the DNS settings to mirror the desktop apps; notably "Use Existing DNS".

This way I could use my local DNS server at home, and PIA DNS / Quad9 / some other private DNS server on all other networks.