Huawei Y6 2019: brightness spins around in a dark scene?

I'm watching the film "The Invisible" with my cell phone (Huawei Y6 2019). The problem, as soon as there's a scene that is darkened, the brightness spins around completely, that the cell phone becomes dark, light, dark light etc

And sometimes the screen reflects so violently that I have to see dark scenes under the ceiling because you can't see it otherwise (and not even the sun's rays shine on it).

That with the from light to dark all the time happens especially when I watch the film under a blanket because otherwise it reflects too much

I already have automatic brightness off: / what can I do?

Switch off adaptive brightness.

Dispose of your cell phone and buy a decent one 😜😁

My Huawei Mate 20 Pro doesn't do that 👌👍👌👍

Boy, if you don't have a clever answer, pull a leash!

👌👍😜😁😎👌👍😜😁😎

Autistic?

👌👍😜😁😎👌👍😜😁😎

And you a hero!