hmm...thats why i hate amoled display...i see it every week in my work - approx half year old samsung phones with burned displays 😞
Here is only one "solution" - you can test to overburn it. Test to play this youtube video in fullscreen and full brightness...or search on store something like galaxy burn fix.
If is fx display 21:9 then search for another video
For future is needed to set brightness to approx low, enable anto brightness, better no static images with high contrast and maybe set quick display timeout....yess amoled is shit 😞