no. i believe you're talking about how existing x11 programs can run under wayland through xwayland. kde plasma as of now can still operate as an X11 DE.

i usually use dmenu_run for starting programs, and bind a key(f11) to run xterm on mouse cursor position. not really what you're looking for but it's quite usable

not really, but .ml kinda has a bad recognition due to numerous issues with some people on it

it's obviously a typo of 'their' lol