Resolution scale threshold for 4k

I don't understand this setting, would nice if someone could explain it to me, because Google wasn't a help here.

What should I set this to for the most games to work properly? I have the feeling most games don't scale right. Right now, this is set to 68 x 68.
I have a Ryzen 7 5700x, 32 gb of ram and a rtx 4070.

Thanks.

 :D