I have Sapphire Radeon RX 5700 Pulse and 20.1.3 radeon drivers installed on Windows 10 (1809).
I can't watch 4k youtube videos because my cpu can not handle it - task manager reports 100% utilize CPU and only ~5% GPU, so GPU is not used (2k and 1080p are played because cpu can run it). Hardware acceleration on/off in firefox settings does not have any effect, chrome does not work at all - videos just not start.
Also I get black screen on both monitors on 3-5 seconds when browsing on firefox, after it firefox is not rendered (gray window). It's happening once or two in a day.
And once in a day (or two days) system totally freezes after start.