Not Luna display or taget display mode! Target display mode don't work with M1 Mac's and luna display can give pixelation when the picture changes. I do have a luna display to but prefer the setup in this video. This is a stable solution using cables.
You do need usb 3 on your Imac for these adapters. But You can find capture device with usb 2 output and they will work usb 2 models.
this setup gives no problems and can be run through a dock. Only downside is its only 1080p. I like that You don't lose the control of your Imac, but only have your M1 mac control one window on your IMac.
Shot in 1080p but uploaded in 4k to get the most out of Youtube compression :)
If you have questions be free to leave a comment.
cheers
The Old Guy.
