Update Big Sur to 11.4 is taking way too long

If you continue to have problems and have to start over try the following:

#1 - boot into Safe Mode according to Start up your Mac in safe mode - Apple Support.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

#2 - go to the App Store, search for and download the full Big Sur installer.

#3 - run the installer from the Safe Mode.

I've had better luck goring thru the App store than thru the System/Software Update preference pane.

Not the machine, don't worry.

Sometimes these downloads go slow. Never figured out if any routing config in m network, internet connection, DNS or what, just happens. I have canceled downloads like that a thousand times and restarted and sometimes it just starts fast and sometimes it insists to go slow.

But again, don't worry, not your machine. Just give it some time to finish download and update and soon you'll be just enjoying you new Mac.

I don't think there is anything you need to worry about. Every time I have purchased a new Apple computer, I have noticed that during and after the initial set up, it seemed that my device was running slower that expected. I remember this happening the first time I bought the new MacBook Air in 2013. I was reminded of the same thing when I got my M1 iMac 24in in May. After I did the update, I simply restarted and everything was snappy again. I think this is normal when downloading new software before everything is optimized and loaded properly. Hope you enjoy that iMac, I certainly am.

Instead of doing the update from System Preferences, Go to the App Store and download it from there. Extremely quick.