Monitor flickering and double fonts what to check?

Question

Iron

Good afternoon, we assembled a PC, noticed that the fonts are doubled, and periodically the screen starts to flicker (a strip on the floor of the screen).

Windows 10, I heard that a frequent problem with fonts, googled everything as in the manuals, which I just didn’t try, the result was 0.

They thought the monitor was given away under warranty, they checked it, they said

everything is ok, check the video card

They gave the video card, they checked it and said

everything is ok with the video card

In what there can be a reason what to check in general in that case?

Video card: NVIDIA GEFORCE GTX 1660 super
Monitor: Viewsonic vx2458-c-mhd (144Hz)
Motherboard: ASRock Fatality B450 Gaming K4

Video : https://youtu.be/2egW5ut69-E

Tried to connect another monitor and cable, same problem , but it flickers a little differently

Answer 1

The video card has nothing to do with this. This is easy to verify by connecting any other monitor.
Also, it is worth using another wire.

Answer 2

curved cable (90%)
driver glitch

Answer 3

Doubling of fonts is usually a cable problem.