Could you elaborate what you mean by "doesn't have Wayland"?
Krita works fine on Wayland (I just finished using it to scribble out a comic strip, in fact), but is there something specific you're finding that is broken?
It requires a Qt Toolkit for UI upgrade and developers prefer to not constantly be spending labor on chasing the current version of every dependency when they could be doing more artsy things.
AFAIK Krita 6.0 plans on bringing Wayland support & the upgrade.