Steam version on Nobara (KDE Plasma) — double-click doesn't open file, and manual .desktop fix throws "Could not extract

Running the Steam version of Krita on Nobara 44 (KDE Plasma 6.7.3, Wayland). .kra is set as default for Krita, but double-clicking a file only launches Krita empty — I have to drag the file in or use Recent Files. Same known issue reported elsewhere for the Steam build (generated .desktop entry doesn’t pass a file argument).

Tried manually editing ~/.local/share/applications/Krita.desktop to point Exec at AppRun with a file argument (based on a fix I found for a similar issue on Mint), but KDE throws Could not extract executable name from '' when I try to select that file from “Open With”.

Anyone on KDE gotten file-association working with the Steam build?