Unable to save properties. You do not have the right to write in [some flathub app].desktop


I’d like to change the command line of some apps, for diverse reasons.
-For signal, the only way to reduce it to tray is adding --use-tray-icon in the command line.
-Some flathub apps are unable to start without the --no-sandbox parameter.

But i’m unable to do so, it says i don’t have the authorizations to change the app’s parameters.