So, here's the thing:
installed sway,
launching through shell: "uh oh. proprietary open kernel drivers are not supported, use --unsupported-gpu and don't whine in report section if your wm nuke itself."
Ok, launching through requested parameters.
Works fine.
Rebooting in ly greeter.
auth in sway.
"Oops, use the parameters requested earlier."
< So, how to add the --unsupported-gpu parameter to the exec command that's been executed by ly greeter?
Tried to change wayland configs that was noted in ly config.ini, but no signs of success. Now greeter looks better tho.