I've seen some interesting work in doing Wayland by hand:

https://gaultier.github.io/blog/wayland_from_scratch.html

I'd also look at the work done on minimal wayland projects like [foot](https://codeberg.org/dnkl/foot), which supports wayland well and seems to be written by hand (see: https://codeberg.org/dnkl/foot/src/branch/master/wayland.c)

I just have the Makefile do the code generation, it would be annoying for the user, but they can complain to Wayland if they don't like it.