Iphone 16 pro max dimming randomly

I have went through all the settings very thoroughly, and I cannot figure out why the screen randomly dims down to roughly 70% brightness, I do not have auto brightness on either. When I fully power my phone off and turn it back on it usually solves the issue, but occasionally it just dims again after a few seconds of being turned on.

please help if you know what is happening.

thank you to anyone who has an idea.