Disable “Eject” in keyboard settings. It is the first entry under “Sound and Media”

create a file, ~/.Xmodmap, adding the line:

keycode 151 = BackSpace

run

xmodmap ~/.Xmodmap

add that to wherever your startup scripts are for persistence

The keycode mappings I got from xev, kind of like “keyboard viewer” in OS X. Its available in the Solus repo:

sudo eopkg install xev