This is just instane. I have "upgraded" from GTX 1070 to RX6800 yesterday. I was kind of used to that things just work. Now crashes, crashes, and more crashes. Blender - cycles, Substance, even games I tried just out of curiosity. Ttried opensource stack, amdgpu-pro stack, mesa-git drivers. I have also installed Radeon Pro renderer to see if it works. I was impressed at first with the performance, but than it came - crash. Dual booted to windows to check if it hw issue - no problem there.
Seems that Amd on Linux is just a bad joke. What a mess...