My new test system is up and running: Numerous pre-installed apps are disabled for now, especially org.lineageos.weather.provider & openweathermapprovider and foundation.e.weather, because weather apps generally have a reputation for being chatty. For me, chatting all day is enough :))
Use the open-source Android firewall NetGuard Pro version (paid version), because only the Pro version unlocks those functions that are essential for monitoring and controlling outgoing (app) data connections even without root rights.
The update from microG 0.2.14.204215-dirty-noen to microG 0.2.17.204714 (with the option ‘Exposure Notifications’ OFF, which I like) was successful with my tried and tested method.