With Garmin Express (latets version) I can see the number of available updates and can click on them in order to see what kind of updates they are. That works both when device is connected and not connected.
I have four devices registered in Garmin Express, but only the fenix 7 does not allow me to see the update details when the watch is not connected. I had a fenix 7 solar before and experienced the same. It works correctly with a edge 1000, edge 830, fenix 6 pro and forerunner 245M.
Any idea if this is a bug and an update of Garmin Express is necessary?