Running live, installed to HD, or live/custom USB drive (or frugal)?
If you're not installed, the zero-thinking "easy" (sic) answer is to see if anything (live) upstream supports it (antiX, Debian bookworm).
I can't deep-dive this moment. If you want to do the work yourself, figure out
what driver you need for that card, dig into
what it supports, and whether or not you have firmware
Code:
ls /usr/lib/firmware/amd*
for that.
If you've not done the DSL file restore, chances are very high that you do not have all the ATI firmware support (it's all big so some is held-back until the restore operation can occur).
If you're not comfortable with diving into that but still want to work on it here, please post:
Might not hurt to post your /var/log/Xorg.0.log, too.
If none of that is what you want, the direct path is to ask the ATI driver people on the X list (but don't be surprised if there's little/no reply unless you demonstrate having done basic minimal homework first).
https://lists.x.org/mailman/listinfo/
If you figure out what you need and don't have it, we can go from there.