Fetching Data Very Slow

I would not expect the effect to be as extreme as you describe but Clear cache can be a useful first step. For an OS in development this can be important for System apps too.

I regularly use

available from F-Droid.

If the phone is “wasting energy” somewhere then study of Battery usage can pinpoint trouble. Compare especially in a typical time slot

  • View by apps vs
  • View by systems.

In your case you might look for any evidence of inappropriate mobile data switching (common) or mobile data vs Wi-Fi.