I don't know if correlate or no, but I have another issue too with qBittorrent 4.5.5 from Flathub too. I remember than work for 2 days after it broke. The GUI not render completely, I can't see anything. Impossible to manipulate
Please take a look at this thread and see if it helps. Since you are on ZorinOS Lite, it may be a bit different but at the very least it's worth checking if this happens when only programs in the snap package format are available.
There's another software manager called Synaptic that is being proposed that does a better job at handling different packages. Perhaps not as visually appealing but it's worth a try.
EDIT: Try the solutions proposed in link above first. I think they look pretty similar but this example may be specific to ZorinOS Core.
As for your other issue with the torrent client, that seems unrelated to this one. Please open a new thread to get help with that, and remember to give as much detail about the problem i.e., when/how it happens, what has changed since it last work, provide logs or screenshots, etc.
Yes, it happens all the time, everyone who has used GNOME Software so far knows that it is a sieve, errors and graphical glitches in every corner. Despite being a great store to view and install software from APT, Flathub and Snapcraft easily with a simple and intuitive GUI it is a pain almost every time you use it.
You are right. This is happening to me too (endless loading, slow loading, blank installed section, missing search results). Have more too, lately not uninstall too. This occurred with 3 programs. When I check in menu, the icons of programs uninstalled is stay in same location and executable yet. In store Software, I have to try 3-4 times search to get full results right.