Hey there, I think using D-Bus to create NetworkManager profiles via your app is the way to go, but you don’t need a ton of special logic to assign a priority to interfaces. By using autoconnect-priority and autoconnect=true on two connections the NetworkManager should be able to handle the rest. Just set 10 of your devices to prefer one interface over the other, maybe based on an environment variable set via the Dashboard?
Here’s another forum link where a user accomplished a similar thing: