So long as your card is a Volcanic Islands, Southern Islands, or Sea Islands card, then the kernel compile parameters should do the trick! Your card fits these parameters, as it is Rx 200 - and an SI card. It should be noted that any SI/VI/CI card, or terascale 2 card more broadly, running on AMDGPU could cause bugs.
Luckily, there is no other real information on this other than Arch Wiki and this article -- so you are in the perfect place! The instructions that I lay out in this piece should work for you. If you have any problems, feel free to write another response or dm me on Twitter.
I did this years and years ago without this article, and just finding good documentation for it was difficult -- especially since VI cards are not even listed at all when it comes to amdgpu!
Here's a bit more info on amdgpu, specifically enabling it for your card:
https://wiki.archlinux.org/title/AMDGPU#Enable_Southern_Islands_(SI)_and_Sea_Islands_(CIK)_support
Here is a bit more info on Rx 200:
