SUMMARY

I opened settings. When I swapped from default 60 Hz screen refresh rate to higher one that my monitor supports - frequent screen flickering started to happen until i changed back to 60 Hz or I turned off compositing. Some internet "solutions" like setting fps manually in kwinrc file under [Compositing] section didn't do anything useful so I reverted them. Changing some compositing options didn't help either.

STEPS TO REPRODUCE
1. With my hardware -  in kubuntu LTS just set 144 Hz / 165 Hz screen refresh rating

OBSERVED RESULT

Screen flickering similar to the one in this video https://www.youtube.com/watch?v=Tlq5rEf5fO4 but with blank white color covering whole screen everytime it flickers. Frequency of flickering varies but is high - from twice per 5 seconds to once per minute. Goes away if I disable compositing with shift+alt+f12. On wayland it works well, but it seems there is very rare flicker once per few hours, though I am unsure.

EXPECTED RESULT

No screen flickering

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 22.04
KDE Plasma Version: 5.24.6
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3
Kernel Version: 5.15.0-52-generic (64-bit)
Graphics Platform: X11
Processors: 24 × AMD Ryzen 9 7900X 12-Core Processor
Memory: 31.1 GiB of RAM
Graphics Processor: AMD SIENNA_CICHLID

ADDITIONAL INFORMATION
My monitor is Gigabyte M27Q-P. My GPU is AMD RX 6950 XT, which isn't optimally supported by my kernel. Since I'm linux beginner I do not wanna mess with testing newer kernels. Monitor is connected via displayport connector to the GPU.