Vertical & Horizontal Lines problem

Hello everyone! I have a problem, some kind of a grid of vertical and horizontal lines over my videos, both in Davinci and in the rendered video. Ursa Mini 4.6k, 18-35 sigma, RAW 3:1, 4608x2592. It looks like some scaling issue, but I can't figure out how to fix this. The grid disappears if rendered at 1920x1080p. Any thoughts?

How does it look when you get it off the computer and onto a calibrated display?

Oh my... I found out that it looks totally fine with another player, or on my smartphone, thnx! But still have no clue why I get this grid in davinci

Bad GPU scaling. I've seen it.

(That's why you can't trust the computer monitor. )

Ok, thnx!)