Hi!
I have such a dilemma, after locking the screen, the password window does not appear the first time, the screensaver blocks this attempt again and again. It doesn’t matter what I use to wake up the computer, mouse or keyboard. It gets dark again, the password entry window disappears.
Thanks!
Hi and welcome to the purple side 
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What is your desktop environment? XFCE, KDE, GNOME, … etc
XFCE, dm sddm
Sounds like this issue. https://forum.endeavouros.com/t/xfce-lock-screen-flashes-erratically/