Fixing new desktop Steam UI

As I'm not a fan of the new Steam UI, I added the -vgui launch parameter to Steam on my laptop to revert the UI to how it was before. As trying to do this on the Steam Deck in desktop mode told me I didn't have sufficient permissions, I tried it again after using Konsole to take ownership of the Steam shortcut, however even then my attempts to add -vgui to the Arguments tab of the shortcut's properties are not being saved. Does anyone know how to make Steam launch with the old UI in desktop mode on the Steam Deck (without using Windows)?

Edit: Figured out how to do it. If you open the Steam shortcut (.desktop file) on the desktop in KWrite and go to Line 30, you'll find the shortcut's launch parameters. Adding -vgui to the end of that line and saving the edit fixed the issue despite the same modification made via the Properties window not doing so. If it still doesn't save, you might need need to take ownership of that shortcut file via Konsole using 'sudo chown deck:deck /home/deck/Desktop/steam.desktop', though try without the sudo command first.