First of all, Wayland is NOT an replacement for X.org server, then a desktop environment for X will glorious fail on Wayland.
Secondly, there is currently no support for the NVIDIA binary blobs in Wayland, only for Nouveau. You have to chose between Nouveau and Nouveau as driver alternatives.
Thirdly, to run Plasma5 in Wayland, you will need a special build given by AlienBOB, and found there:
https://slackware.nl/alien-kde/current/5_wayland/ and not some SBO packages. Yeah, is more complicated than it looks.
Finally, you probably will notice that you will gain nothing running Wayland compared with X.org, and it is rather very limited. And it will always be, as Wayland was a thing invented for tablets, not for desktops.