As I mentioned in my previous post, gnome-software was uninstalled from my system due to an update. I do not have pureos-desktop, and I did not try Mladen’s suggestion. (I am not avoiding his advice; I just didn’t.)
Recently, I decided to debug this problem, but when I installed gnome-software again, it all worked for me. Something must have changed in the interim.
Perhaps you might try that after the latest updates or forcing a reinstall? I cannot predict if it will work; I can only convey my experience.