2022 Mac Mini M1 using 2009 Imac as a Display Question - startup issue

Sorry as i know this topic is likely been beaten to death .... I have a 2022 Mac Mini M1 and want to connect to my 2009 Imac 24 inch (early using El Capitan OS). I have been following some community chats that position that unofficially one can link the two via connecting both units using a USB-C to miniport Display cable. I have tried this approach without any luck of having the Imac serve as the monitor. Any experienced guidance on what I might be doing incorrectly? Correct cable, start-up ?? Any thoughts would be beyond helpful. Thank you.

Mark B