Some apps have own push messaging services (WA, Signal,...) others depend on PlayServices. Back in LOS-times with microG I could see which apps use messaging notification. Is this possible here too?
Background:
I observed that order of installation might be important. So installing an App before Playservices, it won't work with playservices and consumes more battery. Right?
Any way I can check that? What apps do I need to reinstall after PS?

    starbright So installing an App before Playservices, it won't work with playservices and consumes more battery. Right?

    Installing isn't really the problem. As far as I can tell, most apps check for Google Play the first time they're run then never do so again after that. You probably don't need to remove then reinstall the apps, you probably just need to clear the app's storage after installing Google Play.

    Also, apps won't always use more battery. That's just if they run in the background all the time, like Signal, to constantly check for notifications.

    starbright Any way I can check that? What apps do I need to reinstall after PS?

    Not really. If I were in your situation, I'd just clear the storage for apps that I need notifications for so they can set things up with Google's push messaging service on their next "first run."