

Things I’ve run into:
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Out of the box, the lock screen comes on after screen unblanking - late enough that when things aren’t snappy you can briefly catch the desktop without reauthing.
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Sometimes randomly after wake, keyboard input is not recognized in the password field at all. Except for Esc, which in this state appears to crash-restart it and makes it work again
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With a multi-monitor setup, I have still not been able to properly force the primary monitor. Is an issue because things like notifications and the login input will only show up on a usually turned off projector. This one might be PEBCAK.
I have issues 1 and 3 with XFCE on lightdm, too, though.

Did you look this up?
What do you think is more likely - that KDE Neon does not have a testing version of Plasma Login Manager or that a sensationalistic news headline is not giving you a 100% accurate and complete understanding?