Battery drain after iOS 16.3.1. and also increase battery percentage without charging after restart or power off

i got ipad pro 11 m2 2022 for pubg mobile game. Before ipadOs 16.3.1 its battery lasted around 5 hour 30 minutes in Pubg game . And after ios 16.3.1 its lasts maximum 2 hours. and also it increase battery percentage without charging after restart or power off. Like when it was at 80% percent after switch off device it goes upto 83% etc. here is my screenshot you can can clearly watch the battery percentage increase without charging after restarting device. Kindly help me thanks