I’m asking for Android specifically, but I’m curious what else is out there.
For example, some apps work without internet but may use it if it’s available. I might want to block that without having to turn off wifi, force stopping it, and wiping the cache/data.
Similarly, maybe I only want to use the app over a VPN and want to prevent accidentally opening it without first turning the VPN on.
Came here to say NetGuard, too.
I did the allowlist approach and first blocked all and everything and then fiddled with the permissions and now have a good set of settings for stock Android. It’s doable within a few days while regularly using the devices and then allowing things as soon as you notice something does not work as expected.