Luna Display lets you wirelessly use a Mac as second Windows monitor | Ars Technica
Apple iMac Retina 5K 27" Review - NotebookCheck.net Reviews
Incase anyone ever needs the answer…I have a 27” 2010 iMac working in Target Display Mode with a M1 MacBook Pro using a miniDP to USB C adaptor that's capable of 4k60Hz.
5K iMac: Creating an external display with a server inside | Mykola's blog
Used Apple iMac 27-inch (Retina 5K) 3.6GHZ 8-Core i9 (2019) MRR02LL/A-BTO - GainSaver