Welcome to the forum. This is for the upcoming G65 so you won't get much response. Try posting it in the G05 forum and you should get a lot of feedback.
https://g05.bimmerpost.com/forums/fo...play.php?f=704
A few things, 50 miles would be uncommon to get on the 50e, you may be thinking of the European WLTP rating. Shooting for 40 or so is pretty good. The range shown on the screen has nothing to do with what you will get, that is based on the last 18 miles or so that was driven.
Sounds like you are charging at Level 1 which has had problem in some instances so that may be playing into it.