The sandboxing is not always weak. On most apps its almost fully locked down and has access to only your downloads folder. Its only things like vscode which need everything.
You can also manually set permissions using flatseal to lock it down as much as you want.
Putting a blue shield on "sandboxed" when allowing (write!) access to my home directory falls on the extreme side of "weak" to me.
Sure, they are capable of locking it down better. But they haven't in 2+ years. It shows where their priorities are.
Flatseal I'll have to look into though, thanks! A user-controllable method is always a plus, and I do love sandboxes. Most apps need very little access, and locking them down prevents a LOT of kinds of misbehavior, intentional or accidental.
Access to a shared downloads folder doesn't sound “fully locked down” to me. I can imagine situation where I wouldn’t want one app to see what is downloaded by other apps.
Would be better if each process had its own downloads folder (it’s own file system namespace even).
Each flatpak app does have its own namespace and dir it can save whatever it wants to. Some packages like the MS teams one have been given access to downloads only so you can share files with people. You can turn off this access if you want.
Flatpak also has a thing called portals which let the program request a privileged filepicker so the user can select any file and the filepicker grants access to it for the program. The problem is not all apps are set up to work properly with this right now.
TBH I don't know which I prefer. But I suspect the lack of security patches will continue to get worse and worse as time goes on.