It seems each time Valve do a big update to the Steam Deck with SteamOS, it ends up breaking the Decky Loader plugin system but a fresh update is out now fixing it again. From what one of the developers said it now works well across the Stable, Beta and Preview update channels.
There's some known issues including Valve breaking some things on the Preview branch that may need you to restart Steam, if you open the Quick Access Menu right after booting / sleep you may not see the Decky Loader icon until you re-open the menu a couple of times and for people using the Animation Changer you need to re-run the installer.
- Add timeout to get tabs request, wait for network online target before booting decky
- Merge Tabs and Injection Fixes, bring back native Valve toaster
- Systemd service updating
If you've not seen it, check out my guide and intro below with a few plugins being shown off: