Wayland seems ready to me but the main problem that many programs are not configured / compiled to support it. Why is that? I know it's not easy as "Wayland support? Yes" (but in many cases adding a flag is enough but maybe it's not a perfect support). What am I missing? Even Blender says if it fails to use Wayland it will use X11.
When Wayland is detected, it is the preferred system, otherwise X11 will be used
Some applications, such as those with tablet demands, are not met by current wayland des with proper tablet support and xwayland is currently the better option. This may have changed in the last year or so, but this is roughly my recollection of certain big art programs.
Xwayland doesn't get input in some special way, it uses the exact same Wayland protocols to get input events as native Wayland apps. All claims about it being more complete or anything like that are nonsense.
Krita forces Xwayland because they have some X11 specific code they haven't bothered porting away from, that's all.