I've been looking for the same for a decade, but not very actively lately. And I still don't know of anything ready made and working without a fuss. Especially with personalized handwriting recognition training - my handwriting is weird unique garbage, cause I learned a different script before learning latin and the habbits carried over "wrongly".

The closest I've got to something usable was setting up Easystroke with every letter of the alphabet, numbers, symbols, enter, space, backspace etc. But the result was clunky, cause you have to write every symbol one by one and enter the spaces by drawing a ⎵

I don't even know if easystoke would work on wayland. I did this so long ago, there was no wayland in any DE.

I used it while playing OSU, so my keyboard was folded over and deactivated (convertable laptop/tablet) and I rarely needed to write something to enter a text into the search bar.