Hello!

Do you hate the watermark preview banner?

Add the text HideDesktopPreviewBanner=true just after [General] in the file ~/.config/kdeglobals. You will have something as the following:

[General]
HideDesktopPreviewBanner=true

Better for OLEDs displays, stylish, auto-suspend all-blacks displays, etc.

Src: https://invent.kde.org/plasma/plasma-workspace/-/commit/b15d9f41f7f41210b1dd5a78dc1b1894bd40c3dd#16f843a94440a858a2387e36472454ab5685e179_193_196