I recently tried to get Wayland working. Followed a simple guide to enable some NVIDIA boot parameter. Somehow it fucked my complete grub and I couldn't boot until I messed around a fair bit with live usbs. Cost me a whole evening.
So I guess what Wayland is missing is normal support from the GPU manufacturers.
Nvidia didn't want to play nicely and give standard APIs.
Their work around was other extensions that don't actually do what's needed, but sort of works in some scenarios.
All the GPUs I've used work fine, it's a Nvidia throwing it's toys out the pram situation which should hopefully get resolved as they open source the high level drivers and so the correct APIs can be implemented.
Nvidia don't give a shit about Wayland. The reason they're adding explicit sync is because it was implemented in the kernel. They don't care how it will be used or by what.
I don't know how you messed that up, usually the switch is as easy as it can be, and the issue comes when using it, for its lack of explicit sync, causing apps to flicker, and frame pacing in games to be plain bad
This is being fixed in the next two months thankfully
Edit: Taking about Nvidia wayland support here, AMD and Intel are great