In the earlier days of Wayland I was not able to reproduce the custom keyboard mappings that I set up with xkb. Xkb worked, but only in windows running under Xwayland. I know the common xkb presets, like changing caps lock to a control key, are reproduced in Wayland implementations. I had really custom mappings that required more general remapping capability.

I fixed my setup by building a keyboard with a microcontroller that I can program with ZMK. It's a better setup, although it did take more time, effort, and money. The bottom line is I'm enthusiastic about Wayland, even though I had to find another way to reproduce one of my favorite features.