After upgrade to 15.0.1 my battery stuck at 93% for 1 hour now and I'm still confusing about that. If 4-5 day from buy iPhone 13 Pro my battery start to learning optimizing - it seems goodBut I'will add post in next 7-8 hours how battery will drain.
To be honest I have had a iDevice that had the battery percentage stuck.
Make sure this is not the case.