On my 2016 Intel MacBook Pro MS Office apps took about 1 minute to verify...and the same is true (maybe a bit faster now) on my 2023 M2 MacBook Air.
If yours are taking 3-5 minutes to verify, it's highly possible you've got something hindering the performance of your iMac.
Do you have any anti-virus, Mac "Cleaners" or "Optimizers" installed...or VPN software installed. Put simply, those simply aren't needed on a Mac, and they inevitably create more issues than they prevent. (The ONLY use case for VPN, in my opinion, is if you need to connect to a corporate server that requires a VPN connection). If you have any of those, use the manufacturer's uninstaller to erase them, as simply dragging the app icon to the trash will not, normally, remove everything.