Suddenly, I cannot get to the login screen in KDE Neon after rebooting.

Just before loading sddm login screen, the cursor appears before the black screen, and I can move it, but nohing happens afterwards.

I can load virtual terminal (with `ctrl + alt + f2`) and login in the text console. But when I run `startx`, a cursor appears before a blank screen, and nothing happens. I can move this cursor as well.

I don't think I recently changed any settings or system file which may break the system.

Please let me know which log files I need to post.
The system was last updated on 25th April (just after 20.04 version of the major kde softeares were released).

I assume you tried pkcon refresh and pkcon update on the terminal, this has many times fixed the blank screen with just the cursor problem the happened to me.

I'm not sure which log file to look at, but go to the /var/log directory and look for the ones most recently modified (ll -rt) and look at them for hints what might be causing the problem (like maybe boot.log and Xorg.*.log). One of my issues for failure to boot was a hard drive error (not my boot drive) that caused it not to boot (I had accidentally bumped its cable off when I was inside the computer). I saw the error in I think the boot.log file.

It got fixed after updating.
Thanks