hey, I think we have the same problem, I use 5500 xt and having this problem in hunt:showdown, it happens 1 or 2 times in one session. If I restart the game it happens again. I found what is going on when this is happening, system(ntoskrnl) is having %100 usage of the core that is game is already using, it stays about 1 minute or 2 and its okay after that. I used bug report tool and reported this to AMD
Can you check your cpu cores when you are having this probem? U can use msi afterburner, be sure you monitor all of your cores separately, because it only uses 1 core %100 and others are okay and average usage looks normal because of this.
Btw I didn't have this problem with rx580 just 10 days ago. I installed 5500 xt and it's here.
I tried cleaning and installing lots of different drivers started from the first driver of 2020, clean windows format, updated motherboard bios, nothing helped.
And at the same time I have one extra problem, if I enable instant replay, game starts to stutter after some time, 1 extra big frame time every 5-15 seconds. Here is the video of it https://www.youtube.com/watch?v=GDY2FZbK2TU
If I disable instant replay this goes away, but I coulnd't find any fixes for the problem that is similar to yours.