Nah, touchscreen keyboards on Linux and especially KDE are severely lacking. I think there are efforts underway to make a new keyboard for kde because Maliit has been abandoned. But I have no idea how far they are.
I managed to get ~~Onscreen~~ Onboard and Steam's keyboard to work on Wayland. But they are both not ideal either. Onboard especially seems to be prone to crash when used via touch on Wayland. Let me find the posts I made on the subject...
Edit: Here's Onboard: https://swg-empire.de/post/842090
Edit 2: And Steam: https://swg-empire.de/post/853437