because they will drain and ruin your battery and don't worry, nothing will happen to your phone. for PlayStore you can use ApkMirror.com or ApkPure.com or just search google the app you want.
If you want a Great Battery life, go to Application Manager, (hit 3 dots and select Show System App) and disable all google apps. All of them, even playstore and google play services
If you didn't the problematic app, consider to do a factory reset and for some day don't install any apps and see of the problem is still there or not. I'm sure it won't be
