If you have the inclination and skills, it can be converted to an absolutely-zero-smartness display using an LCD driver board (this example conversion log used the A1419's housing with a separately purchased display panel): https://forums.macrumors.com/threads/diy-5k-monitor-success....
Someone needs to turn iMac-to-monitor conversion into a small business. At least in major cities, since packing up an iMac for shipping is not easy or fun if you don't have the original box anymore.
It was about $250 all said and done. I got lucky and got the iMac for free, though even if I had purchased the Mac it would still be more affordable than Apple's Studio Display.
