Well, indeed. If you can't find a way to go one-level-up, that is to say, blocking at a router/network, hardware, or OS whitelist/blacklist type situation, i'd respond that the responsible thing to do is to blacklist the app.

I realise of course that not everyone will like that response, but i'd also say as non-flippantly as possible, that mature responsibility is, almost by definition, not participating in things you might otherwise wish to because of higher-order principal-based concerns.

Stop using that app. Stop using ecosystems that allow for it to take it a step further.

Pi-hole (https://pi-hole.net/) might work for some apps.

I'm sure there's... an app for that. ;-)