I have a AMD Ryzen 2400G and use it with onboard VEGA 11 Graphics.
To run my screen in 4k 60Hz resolution it is constantly flickering, after i turned
the screen (Samsung) off and on the issue disappeared.
I have a gigabyte a320-s2h motherboard with onboard hdmi class for 1.4/ 2.0b
Since Software Adrenalin 2020 Edition 19.12.2 (WHQL) the flickering issue is
totaly disappeared. Good work by the developers of AMD, you resolved the issue!