It looks like this post should help:
Also appears to have a couple links farther down that may prove useful.
Hope this helps you get it working.
Edit:
With no wayland, I do not have the option of choosing x11/wayland on the logon screen. I can duplicate your inxi
ouput prior to a logout, and after installation there is a dropdown in the lower left for x11/wayland, with the default on x11 (which you see?).
Your output indicates that the 3 items KDE wants to install to use wayland. If you are not seeing the dropdown with the two choices, I would suggest
- System->UpdateInTerminal from the menu or
sudo pacman -Syu
from a terminal - reboot your machine
If it is still not working come back with results, and anything else you may have tried.