- Install CachyOS's cachyos-vapor package instead of extracting Valve's
steamdeck-kde-presets into ~/.local/share, and remove it again on disable
if the wizard installed it.
- Apply the Vapor global theme with "Desktop and window layout"
(lookandfeeltool --resetLayout): Steam Deck wallpaper, SteamOS panel and
launcher icon. Layout files are backed up and restored, every key from
Vapor's defaults goes through the undo journal.
- Restore the real previous color scheme (CachyOS's inline BreezeDark colors
have no scheme name), and clear ColorScheme before plasma-apply-colorscheme,
which otherwise skips an already named scheme.
- Register Vapor as the dark theme, so Plasma's Dark Mode toggle shows on.
- Drop the SteamOS desktop defaults (GTK, Konsole, gsettings, panel tweaks).
- New lib/steamos-extras.sh, downloaded from Valve's newest
steamdeck-kde-presets (checksum verified) into /usr/local: Add to Steam,
Nested Desktop, the gaming-return icon for Return to Gaming Mode, the
Steam Keyboard window rule and an empty KWallet (only without a wallet).
- single_launcher: re-apply single user's launcher settings after the
layout reset replaces the launcher.