Talking about the similarities, I first of all also have a white spot on my screen, only one though. Well I checked it's probably hot pixel and I think it's not covered in warranty. The only way you get rid of that is by replacing the screen. Or second option is live with it. But what I have done is that I have put everything dark mode, so it's not clearly visible on dark screens and hence it doesn't annoy me.
What's interesting is the second similarity that, I also have that horizontal weird "rubbed" type mark in the center exactly like that.
So now what I am thinking is that there might have been some issues in manufacturing of our units.
Just to confirm :
1) Did you also but this laptop in Big Billion days of 2019?
2) Did by any chance at any incident, red ants entered in your laptop?
Hoping you respond!