External Monitor Issues
Anyone know how I can get a 2017 iMac to work as an external monitor with a 2020 MacBook Air?
no
Note: Target Display Mode isn’t supported on iMac models with Retina display. Only iMac (27-inch, Late 2009), iMac (27-inch, Mid 2010), and iMac (Mid 2011 to Mid 2014) support Target Display Mode.
https://support.apple.com/guide/mac-help/use-an-imac-as-a-display-mh30822/mac