I think this will be helpful for you
[link|https://okadtech.com/how-to-fix-black-spots-on-phone-screen/|https://okadtech.com/how-to-fix-black-spots-on-phone-screen/|new_window=true]
You can try the solution to solve this problem.
I was facing this issue in my iphone x tried this article solution it didn’t work.
Tried the same solution in a others phone it worked.
Conclusion - If the pixel is dead then you can’t repair it but if it’s stucked then it can repaired.
I dropped my iphone x so maybe the pixels are broken so i unable to solve this problem. I have to replace my screen.
It all differ.