This is a great starting point. Looks like your graphics are in order.
This means you are ready to read this thread:
Thread trying-to-run-kde-6-plasma-with-wayland.93951.
Some comments in that thread mention that one needs to enable
seatd in
/etc/rc.conf. And the command for starting KDE Wayland from vty has been ironed out, too. Details are in the last few pages of that thread.
One caveat: Some people use packages (as up-to-date as practical), I compile from ports. Important part here is to be completely up-to-date. Pkg is a mess on FreeBSD, esp. when upgrading.
So pay attention to the versions of the stuff you use, and mention them in this thread, this will help the troubleshooting process.