As my friend reported that with his Mint 19 (= Ubuntu 18.04 LTS)
with Nvidia Graphics he does not see the graphic bugs (neither
in FullHD nor in 4k), I just tested it again and will provide further info:
My HW is AMD system (AMD Zen 2 {Ryzen 5 3600} & RDNA1 /
Navi 10 {Radeon RX 5700 XT}) using 4k;
1st used OS was Kubuntu 20.10 STS Groovy (EoL) with
Linux 5.11.16 and Mesa 21.1.3 both via PPA - my gaming platform
I can gatantuee that no graphic bugs have occurred in Unity games
(having more than 270 Unity games all tested on that system).
I checked with KDE neon partition (HWE kernel 5.11.0-41 &
Mesa 21.3.1 kisa PPA) and the blinding bugs are just the same ...
so does not seem to be a driver problem ...
I hope this can help to bring some light for getting a fix.