I’m fully aware Darktable is NOT currently supported under Wayland, but hey - trying to make it work, as we are currently on the crossroads with Wayland gaining momentum and X11 retiring.
The current situation for me is cursed, to say the least. 
I’m running Arch KDE Wayland with AMD 6650XT GPU using MESA drivers.
I tried all three OpenCL flavors - Rusticl, OpenCL AMD and Rocm.
The smoothest running for the system was Rusticl, but alas, it’s under heavy development, so some modules do not work in Darktable. It’s just not usable.
OpenCL and Rocm both work but under Wayland the system is highly unstable when using Darktable or Gimp.
Darktable can freeze the system upon start. If not, there’s a chance during editing the image will enter the endless loop displaying ‘opening xyz file’.
Similarly, GIMP can do the same - upon trying to open a file it will be stuck there. No KILL command could terminate those two apps.
Even if everything went out smoothly, sometimes the system cannot reboot nicely - it will be stuck, unable to finish or kill the program running (either Dakrtable or Gimp).
So I have decided to switch to X11.
All my problems went away. All OpenCL drivers worked nicely, no crashes, no freezes, no instabilities. Fast and smooth. I was finally happy.
Until I tried to play a game with Steam Proton. In X11 games stutter compared to Wayland experience that is fluid, where games work without any delay. On par with W11.
So I have decided to switch back to Wayland, to uninstall OpenCL (actually Installed Clover Mesa, but it does not support Darktable) and be done with it. The system is stable, but I don’t have OpenCL support for Darktable.
If anyone managed to sort these out under Wayland and AMD, please share here. In fact, please share any of your experiences with Wayland and OpenCL.