Auto Brightness change on iphone 12 pro

My new iphone 12 pro has issues related to the auto brightness issue. I play games specifically COD and if I continuously play the game the brightness of my iphone suddenly sets itself automatically to 50% and if I try to manually change it/increase the brightness remains intact at 50% . If i decrease the brightness it does but the value of brightness is set at 50% and cannot go beyond in any circumstance.

I had already disabled the auto brightness feature and rest of the other things as well.

i had raised the issue with apple support team and they asked me to come in to get further support. Ive also recorded a video to show the issue.

has anyone else encountered this issue.