late 2014 mojave on iMac, migrating to new iMac 2022

Welcome to Apple Support Community.

Congratulations on the new Mac! To move your data, restore from your Time Machine backup: Restore your Mac from a backup - Apple Support. You should not use Wi-Fi or any other method as they often fail.

If you do not have a Time Machine backup, you should create one on your old Mac so it can be restored to the new Mac. To start, you need an external hard drive. Here’s an excellent one sold by Apple: LaCie 2TB Mobile Drive External Hard Drive USB-C - Apple. If you have an iMac (Late 2015) or earlier, or a Mac mini (Late 2014) or earlier, you will also need this cable. iMac (2017) and newer computers do not require this separate cable. You can then follow the steps in this Apple Support article to setup your Time Machine backup: Back up your Mac with Time Machine - Apple Support.

Once your new Mac is setup with your data migrated, you should setup Time Machine again to keep continuous backups of your data: Back up your Mac with Time Machine - Apple Support. 

Jack

You can use it as a Time Machine backup External Hard Disk if it has adequate space which should be about 2x-3x the capacity of the amount of storage you use. So if you have about 512GB of storage used on the old Mac then you should have a 1TB - 2TB model. If your old External Hard Disk is 4-6 years old, this would be my #1 choice.

Another option is to use it to store large media libraries, such as you photos, music or movies. This is wise as it preserves the internal storage on the new iMac.

Yes, please follow the steps in Setup Assistant and Migration Assistant and you will find your migration to be simple, fast and complete.

A couple of notes, please ensure the new Mac has the same amount or a larger capacity storage than the 2014 iMac. For example if the 2014 has 750GB of data stored on it and the capacity of the new iMac is only 512GB then you are going to fail. The new machine in this example would need to be a 1TB or larger capacity SSD.

So, two questions: (1) The 2014 iMac is being run from a Samsung PSSD disk. Would it be possible to keep that disk running Mojave, running separate from the OS on the new iMac? You cannot run an earlier version of Mac OS on a machine than what it originally shipped with, so no. However if you keep the 2014 running Mojave you can retain that app. My suggestion is to either upgrade the app or replace it with an app that is a 64bit app that runs on Monterey. You will need to check with the developers of said app(s). (2) Should I upgrade the OS on the 2014 iMac before I migrate to the new computer? Nope, there is no need to do that.

That's fine. Your migration should be smooth and fast.

It sounds like your migration went well.