iPhone XS Max Maddening Brightness

I want the brightness on the phone to be the same no matter what. I have true tone and night shift off. I have the most recent iOS. The brightness keeps changing. I have to stop what I'm doing and fix it.

I read elsewhere that I had to turn off Zoomed view. Which I did but the problem did not go away. It got worse.

Frankly, having to turn off Zoomed view is not an acceptable fix. There is only one acceptable fix: unless I turn on True Tone or Night Shift, the display should not change unless at my direction.

I do not want my phone to change the brightness settings on its own. Ever. Period.

Suggestions?