Should migrate ‘Setup’ from my old iMac to my new one as part of the transfer?

It doesn't work that way. Here is an overview of the steps involved. Migration Assistant is a program provided by Apple for transferring your files from your old computer to your new computer. It is very easy to use. Be sure to read and follow its instructions. Basically, the process is as follows.

You first begin by starting the process of setting up your new computer. You will be asked if you wish to transfer files. Respond YES and follow the instructions you will be given.

You will be told to turn both computers on and activate Migration Assistant in the old computer.

The computers should be connected with a USB cable to facilitate the transfer.  Wi-Fi is simply not suited for a transfer of so much data and corruption often results.  Do not use it. It can corrupt or lose data.

You will be given several options as to what to transfer. You will likely want to transfer your settings and preferences.

You can transfer all or none of your files. You do not have an option to select certain files to transfer. If you wish to do that, then do so manually.

The old computer's operating system will not be transferred. No data from the old computer is erased.

Allow for up to an hour for the transfer process to complete once you start it.

It should set up the new computer the same as the old one excluding the operating system.

Enjoy your new Mac.

I hope this is helpful. Good luck.

My feelings on this question are based on years of experience with Macs (and Windows too).

This works best if iCloud storage is enabled on the old Mac and backups have been made on external media.

Find and make a note of the registration numbers for all your apps, to be used later.

• Perform a clean (virgin) install of the MacOS on the new machine (if not already installed with the latest update)
• Afterwards download and sequentially install the latest compatible versions of the apps you regularly use and check each one for issues before moving on to install the next one. Do not install anti-virus or cleanup apps.
• You will have linked your new Mac to your Apple ID and if you enable iCloud you will access all the files stored there.
• Use the other backup to transfer files only to the new machine.

The rational behind this is that old computers pick up and retain lots of orphan files and if you just mirror your old setup across to your new Mac there is a higher risk of problems.

This is what I did when I moved over to an M1 24" iMac having had and used a Mac Pro Desktop from 2008 until 2021. I've had no problems with my new Mac.

Yes, I know that the instructions are problematic concerning connecting the two Macs. Incidentally, an Ethernet connection will also work, but will be slower than USB. The problem with continuing is that since the Wi-Fi is too slow for this large amount of data, corruption of the data will often occur. You really don't want that. I would cancel and begin again. Good luck.

The fastest and most efficient way, is to plug your old iMac's Time Machine backup into the new iMac and Migrate from it during the initial setup.