I'd be highly surprised if Wayland actually has a protocol for applications to just type across other applications, we barely even have global shortcuts (it's getting there but reaaaaaally slowly).

KPXC might be able to get around it by using whichever method ydotool does (by faking a device AFAIK) - probably needs root to do this though, and it would also need to implement the global shortcuts API to be able to respond to a key bind I believe.

So perhaps a bit of column A and column B.