[EntrePrescott]

can't test it currently as the machine I have here doesn't run wayland but xorg, but iirc: the general idea of using a dead_greek modifier should also work on wayland, but assigning a key for it unfortunately cannot be done with the simple non-xkb legacy X11 keyboard layout tools like xmodmap that still work on xorg.

That being said, wayland did take over part of xkb (the less old keyboard system) from xorg, and so from what I can gather from a quick search, the easiest way to assign a key as dead_greek in wayland would probably be with a file in $XDG_CONFIG_HOME/xkb/symbols/ like they do here for other key symbols: https://unix.stackexchange.com/questions/292868/how-to-custo...

I don't know any way to tell wayland to (re)load an xkb config on the fly (without logging out and back in) though. In particular, I doubt that setxkbmap would work for that like on xorg.