(MODS, I don't believe this is a necro, since my install issues were the same and different from posters in this thread. If you believe I am in error by check-boxing this compliance button, please dispose of this reply. Not my intention to be out of necro compliance).
I'd say from 1pm to 4pm yesterday, flatpak flathub install did not work for Zoom. That's 180 frustrating minutes. Not really a timeout thing, more like a stops and hangs thing. And by 'stops and hangs' it's usually for twenty-minute increments before I declared it a fail. I could not install Zoom as a flatpak. I'm updated, did reboots, washed my hands, add rinse & repeat.
If someone tries to install it and cannot duplicate that, then some kind of problem on my end.
The post above about downloading, unzipping, and running worked. I'm using it.
**Warning:-if you do download it from Zoom, use the wrapper launch, not the internet. With the internet browser launch Chrome gives you a diag-box that says Zoom needs to access an XDG program. In my case it some dormant baloo_file in there that gets activated and creats 5GB index files in minutes for no good reason. I don't think Zoom snuck the baloo in there. But some install/remove did and I probably wasn't paying attention. It's a kde indexer that chokes budgie until it can't breathe and I spent most of today removing every single file.
Happy about: the package described above from Zoom runs great on Solus.
Sad about: too much proprietary stuff on my rig in these challenging times--I take Skype out the Solus autostart daily and every reboot it puts itself back in. Dirty dirty dirty on them. Uninstalled skype wrapper. I hate Chrome.