there is a like tutorial project that the godot people made but its only for the older versions :(
brute forcing this by emitting a signal everytime a key is pressed then receiving the string : "InputEventKey: keycode=68 (D), mods=none, physical=false, pressed=true, echo=false" and parcing the letter out of it.
Is it the best way, absolutly not. is it the way that i could get it to work? yes