Comment 13 for bug 1850977

I looked at the policy used by PackageKit. I believe gnome-software uses it as a backend, so can you try installing something that is specifically not a snap?

At this point, all snapd does is ask PolicyKit whether given the policy, the user can install a package. PolicyKit responds with yes, therefore the installation can proceed. There's not much we can do inside the declared policy, as the defaults are fine IMO.

From my perspective, this should likely be investigated by someone more familiar with PolicyKit to find out why it's treating your user as admin.