I can't imagine why it would discharge to 70 or 80.
Even if you think you don't have that routine on, check your routines. Also look at you battery graph to see what happens and at what time.
Thank you for your feedback.
As other users have suggested, please check if you have a routine set that stops battery from charging fully. If that is not the case, please use the latest Samsung Members app to submit an error report to help us debug.
We appreciate your contribution to the Beta Program.
One UI Beta Team