I have altered the Window Decorations (added "On all desktops" and "Shade" buttons in the title bar) but the alterations are not visible in windows (even after a restart). I'm using the latest KDE Neon under virtual box (host is MSWindows). I've also noticed this in a similar Fedora 36 installation (again, fully updated). Specifically, the Fedora KDE installation is completely fresh and has its default settings (the first thing i did after setup finished was to alter the window decorations and it is just not working). When visiting Settings again, i see the decorations in place (where i had put them) but they just don't show in actual windows.

Is this a known/reported bug?

OK, to answer my question, i just updated both Fedora and Neon. In Neon, this has been corrected. I guess Fedora has not been updated yet.