Why is the image on the monitor blinking?

Question

Monitors

Monitor IIyama XUB 3493WQSU

The monitor blinks about once every 5-10 minutes during operation. I did not reveal patterns of appearance (open browser, game, movie). I attach the video and also here is the link to the video uploaded on YouTube:
https://youtu.be/_IGIYfiM4-A

Configuration:
The monitor is connected to the PC via the supplied Display Port cable to the Sapphire AMD Radeon RX 5600 XT video card. The monitor itself is connected to a power source through the UPS. Updated video card drivers. I even downloaded the monitor driver (!) from offsite.

Tried:
1. Connecting via HDMI - no effect.
2. Connecting via an incomplete DisplayPort cable - had no effect.
3. Connecting to another power source (another outlet and another cable) - had no effect.
4. Disabled FreeSync in the settings and switched to DisplayPort 1.0 - no effect.

In general, I am very upset with an expensive purchase, although apart from this problem, the monitor suits everyone. The problem is very annoying, you sit working and then suddenly the monitor blinks, which is very noticeable to the eye. What could it be? Is the internal power supply dead? Capacitor? Is there any way to track this at home? Somehow the voltage jumps in the UPS? (!). Curves AMDshny firewood? Please help me guys, I'm really screwed.

Answer 1

A month has passed, the monitor is still blinking. New video:
https://youtu.be/2jbHLcLEVJQ