I administer the Men’s Shed 2020 27-in iMac. The internet connection is via an iPhone’s hotspot. Definitely not good enough to install macOS updates in excess of 15 GB total. We only came out of the latest COVID 19 lockdown last week so there had been no chance to updater to Monterey beforehand. I did the usual thing & downloaded the installer to a USB stick but when I ran the app in the Shed it fell over after two minutes with the error “unable to verify macOS.” This turns out to be related to Monterey & Macs with T2 chips.
So I took the iMac home last night & did the updates over my home broadband without any problems.
I did notice a pleasing oddity in the Shed today after returning it to its normal location.
In 2015 the Shed bought a multifunction laser printer. This worked fine until Big Sur arrived. After that install, the scanner part was non-functional. It would not respond under the Printers & scanners preference pane, Preview, Vuescan or Image Capture. As an interim measure I loaned the shed my elderly Epson V300 film & slide flatbed scanner pending purchase of a newer printer.
The oddity mentioned earlier was that under Monterey, the full scanner functionality was restored.