Slow iCloud set up
iCloud setup on new McBook Pro is taking too much time
Once you erase the hard drive and reinstall Mac OS Erase and reinstall macOS - Apple Support and set up new Mac Set up your Mac - Apple Support the same Apple ID and password with all accounts credentials known to you has to be signed in Sign in with your Apple ID - Apple Support Mac system preferences the iCloud has to be set up Set up iCloud on your Mac - Apple Support again iCloud Drive is to be turned on Set up iCloud Drive - Apple Support
Note : in case if you want to create a new Apple ID How to create a new Apple ID - Apple Support
And inbuilt apps boxes are to be turned on iCloud in the new operating system Set up iCloud features on Mac - Apple Support
Add an email account to Mail on your Mac - Apple Support
Note : Yes setting up new Mac is time taking , it depends upon your typing speed on the keyboard , and entering the credentials correctly , high network speed is essential to configure the settings .