Suggestion as per subject. AFAIK, there is now plenty of FOSS suport for the cards that were caught up with poor support during the time of the AMD catalyst driver evolution.
At that time. I was chasing support for the AMD HD 5700 card and doing the fglrx waltz. Now there is the FOSS Radeon driver that fully suoorts this card.
Weirdly, I now have a AMD RX 5700XT card that I'm chasing similar problems with, although the linux 5.19 kernel supports single monitor (devuan-chimaera//debian-unstable(buster?).
Another perspective is that AMD has mved linux support through four different forums in the last few years. So, 2c as per subject.AMD 7950/7850 with official fglrx AMD catalyst drivers 64bit/32bit support on POL