This may help:

https://khronokernel.com/macos/2022/03/01/5K-MONITOR.html

https://www.ifixit.com/Guide/Convert+an+iMac+Intel+27-Inch+E...

https://www.aliexpress.us/item/3256802134515555.html

https://blog.lewislovelock.com/turning-an-5k-imac-into-a-mon...

https://www.ebay.co.uk/itm/203666708700?var=504097344943

https://mschmitt.org/blog/convert-5k-27-imac-external-displa...

https://www.aliexpress.us/item/3256802548599862.html?gateway...