How to migrate
 

Have 2 iMacs (2017 and 2019) and the newer one is still on Catalina and the older one is on Big Sur. Newer one definitely has fusion drive and not sure on the older one but think not

Just bought external SSDs for both. I have fully bootable SuperDuper backups on external spinning drives on both iMacs.

What is the best way to migrate from the internal iMac drives to the new external SSDs?

Can I just use SuperDuper to copy from the internal (or external backUp) to the new SSD, change the iMac to boot from new SSD, and be done with it?

Thanks

Yes, you should be able to start up from the backups and restore as expected. If you have trouble, drop me a line at support.