How do I hook up my new mini Mac to my 2014 (mid) iMac?
How do I hook up my new mini Mac to my 2014 (mid) iMac?
iMac 21.5″, macOS 11.7
If you're asking how to use your iMac as a monitor for your new Mac mini... there is no Apple solution for that. It's not a thing. Target Display mode used to be a feature of older iMacs and specific other Macs, but it's been retired for years, now.
You might look into Duet or Luna as third party options.