My stuff:

• ArchLinux KDE, amdgpu, vulkan, wayland
• RetroArch installed from official repos
• cores installed via RetroArch utility

I'm using this command but it results in a graphical glitch when launched from steam:

retroarch -L "path/to/core" "path/to/game"

Possible causes I found:

• the command may not work if the game is a .cue file
• loading a game from Steam via RetroArch 64bit can be a problem(?)
• cores installed with the utility are in ".info" and not in the ".so" extension