Not natively, but there is Luna Display. If you don't mind completely taking it apart and replacing the logic board with a custom display board you can follow in Luke Miani's footsteps. - Source: Reddit / about 15 hours ago
The hardware is not compatible with macOS Ventura without using OpenCore Legacy Patcher. Additionally, although your iMac doesn’t support target display mode, Luna Display is one option for getting around that limitation. - Source: Reddit / 3 days ago
You can now buy a third-party device for newer Macs to use the iMac screen - such as LUNA DISPLAY https://astropad.com/product/lunadisplay/. - Source: Reddit / 10 days ago
I have an old iMac 27-inch (mid-2015), which I want to convert into a second monitor using a Luna Display. I also replaced my old monitor with a Gigabyte M32U. - Source: Reddit / 10 days ago
You can check out Luna Display: https://astropad.com/product/lunadisplay/. - Source: Reddit / 11 days ago
Try Luna Display. I use it with a late 2012 iMac and it works well. Https://astropad.com/product/lunadisplay/. - Source: Reddit / 17 days ago
Yes, it can be done, but as far as I’m aware the only way to do it is to use a 3rd-party dongle and app. Astropad’s Luna will do it for both Mac and PC. They even mention headless PCs as a use case. See here: https://astropad.com/product/lunadisplay/. - Source: Reddit / 21 days ago
The only method I’ve come across that allows for what you’re wanting is Luna Display. - Source: Reddit / about 1 month ago
What about this for your iPad https://astropad.com/product/lunadisplay/. - Source: Reddit / about 1 month ago
Since AirPlat to your iMac is not supported, buy Luna. - Source: Reddit / about 2 months ago
Here is a product that provides a superior alternative to Apple’s native connection: Luna Display. - Source: Reddit / about 2 months ago
I researched this a while back. But never tried it. There are YouTubers that show examples. It’s not perfect but could be good enough to use old iMac as 2nd Mac Mini display. https://astropad.com/product/lunadisplay/. - Source: Reddit / about 2 months ago
I use an old Apple TV hooked into my projector. The only other app I can think of is Astropad Luna Display which has a dedicated dongle. It runs about $119, so while it's not the cheapest option it does work. - Source: Reddit / about 2 months ago
You want to check Luna Dispaly, they even advertise what you are asking for (headless mode with an iPad) on their website. Site. - Source: Reddit / about 2 months ago
Target display mode only works for 2009 - 2015 27" iMacs. Luna Display is an option though. - Source: Reddit / about 2 months ago
This isn't supported by a cable, so I'm unsure what you mean about HDMI. Purchase https://astropad.com/product/lunadisplay/. - Source: Reddit / 2 months ago
Https://astropad.com/product/lunadisplay/ is the go to for this, and may fit your needs. - Source: Reddit / 2 months ago
Https://astropad.com/product/lunadisplay/ What about this? It's $120 though. - Source: Reddit / 4 months ago
This might be a decent workaround: https://astropad.com/product/lunadisplay/. - Source: Reddit / 4 months ago
It's not a quick fix but you might be able to use Luna Display and get it to work as a display. - Source: Reddit / 4 months ago
I have Luna Display on the old Mac with CS6. Basically I have the HDD shared and drop the files to my desktop when finished. - Source: Reddit / 4 months ago
Do you know an article comparing Luna Display to other products?
Suggest a link to a post with product alternatives.