iPad plays back some videos too bright
I noticed, when watching some videos on YouTube or other like sites, sometimes the video would be overtly bright.
I found a solution that worked for me, YMMV
Go to Settings
Accessibility
Display & Text Size
Reduce White Point
Slide the setting to 60%-ish seemed good.
I tried reducing Auto-Brightness,
It didn’t seem to do much but may work for you
Good luck😉
iPad Pro, iPadOS 16