After some (expected!) struggles getting the A770 to play nicely -- I had to build and install the 6.2-rc4 mainline kernel, and switch to Wayland -- I do have it working under Linux. For something that's only supposed to be getting, like, 70% of the performance that it is under Windows, it's a screamer, easily claps my 1070 and it's reliable and even does integer scaling! (glares at nVidia)
This thing is a monster for what I paid for it and the software I got with it to sweeten the deal. With the prospect of it only getting better with age, I find myself with no buyer's remorse whatsoever for my first real GPU I've bought new. Yes, that's right, everything else I've had up till now has been used. Except the GT610 and 730 I had back in 2013-2015, but let's just forget about those... Yes, it's a little annoying. Yes, the Intel drivers still kinda stink. That stuff is actively getting better and while it really shouldn't have released in the condition it did, I'm happy with my purchase.