Battery drains completely then won't charge or turn back on

First, always rule out a charging port and 2 brand new batteries in case the first is bad. Aftermarket batteries come bad all the time. Actually try 2 charging ports also as those come bad a lot as well.

Then I would look at the small components right above the battery connector on the board itself. If there was accidental pry damage to the filter, for example, you could have charging problems. Check to make sure theres no loose small components. You have a few small caps and two filters. Should be able to get away with a cap removed but if one or both filters are loose/gone it'll need to be replaced.