Im not sure about this one since they can say that your phone is damaged because you have done something to your device from an unauthorized service centre...
But still give a try by going to the service centre and gettinng your device inspected...
I'm having the same exact problem on my Note 9 and it's bugging for months now. Problem just occurs after a few minutes of continuous use, without changing any setting, even by just watching the screen. Would disappear after resting the screen for a while. Then appears again after several minutes of use.
At first I was afraid it was some kind of hardware failure and that I would just wake up without a functioning screen. (And it kinda embarrass me that friends with much cheaper Chinese phones have no such problem).
Searching up the net I found a battalion out there are having the exact problem on Note 9. And most agrees that it happened after a software update. Probably a hundred Youtubers have some advice how to fix it, but none worked for me.
It kinda relieved me that I'm not alone but then my disappointment and anger is now with Samsung who keeps saying that we should bring the unit to their service center!
If this is a hardware issue why does almost everyone said it occurred after a software update? And if this is software issue, can't they just release a new update to fix this once and for all?
I have been a loyal Samsung user (even a defender) but if this isn't fixed, this will definitely be my last unit with that brand on it.
