Already posted that. Whether Wayland works better or not would be unknown until you install it and try it.
Edit: For problem solving we either need a way to reproduce the problem on out hardware or VM’s or we need some logs. In other words we need to find out exactly what is not working.
The basic system log is the journal invoked with the command journalctl. That will output many lines of information usually to much. To get the logs for users current boot use journalect -b for previous boots you first can run journalctl --list-boots. The next previous boot would be journalctl -b -1 and so on.
So we need the logs for a boot that did not boot properly if the current boot did not boot properly that will work. Put all the output, including the command used, in a text file and post that here. Here is one way to do this:
For current boot:
journalctl -b > journalctl.txt
For the immediately preceding boot:
journalctl -b -1 > journalctl.txt
That creates the file journalctl.txt you can post here. There are usually a lot of line of output.
Something to try:
Boot in to console mode:
Run:
sudo systemctl disable sddm
Reboot then at the command prompt login and run:
startx
or:
startplasma-x11
or for Wayland:
startplasma-wayland
The purpose is to see if you get a graphical desktop without using sddm. This would tell us if the is/is not a cause. If the problem is not sddm then graphic hardware of software become a possible suspect.