Manjaro Linux: Waking up from suspend sporadically shows the frozen lock screen image without UI / black screen with movable cursor

Just dumping my solution here, in case I ever forget. Who knows, maybe it will help someone else, too.

System info:

• Manjaro Linux 21.3.7
• KDE Plasma 5.24.6
• NVIDIA graphics card, proprietary driver

Symptoms:

• 100% CPU utilization by kscreenlocker_greet
• loginctl unlock-sessions does not work

Solution:

• Switch to another tty (using Ctrl+Alt+F2, for example)
• Login
• Kill kscreenlocker_greet using htop, for example

Related:

• https://bugs.kde.org/show_bug.cgi?id=347772