RethinkDNS (available on F-Droid) has a mode where it blocks every connection by default and you have to allow each app to access the network. I used that to effectively disable the pre-installed malware on my Android TV box (X88 Pro iirc). It also has DNS and connection logs to check network traffic (can be a lot though). GlassWire (Play Store) is nice to quickly check for an unexpected amount of network traffic. Not sure if there’s ways around that, but it worked in my case a while ago.
RethinkDNS (available on F-Droid) has a mode where it blocks every connection by default and you have to allow each app to access the network. I used that to effectively disable the pre-installed malware on my Android TV box (X88 Pro iirc). It also has DNS and connection logs to check network traffic (can be a lot though). GlassWire (Play Store) is nice to quickly check for an unexpected amount of network traffic. Not sure if there’s ways around that, but it worked in my case a while ago.