PowerDevil in Plasma 6.0 and beyond - KDE Blogs
Brightness can be increased or decreased in 5% steps […] In Plasma 6.0, brightness steps can also be controlled in 1% steps by pressing Shift in addition to the brightness key.
1% steps works when using the hotkeys, but no longer works when hovering over the tray applet and using the Shift key - this is a very recent issue
Operating System: Manjaro Linux
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.7.2
Kernel Version: 6.10.13-3-MANJARO (64-bit)
Graphics Platform: X11