iMac not recognizing 2nd external display via DP daisy chain
I have a 2017 iMac 21.5" Retina 4K model. Just recently I figured I would try to salvage a 27" QHD display that is a few years old, but works fine, I experienced something I'm not sure about and would like to further troubleshoot on the Mac if possible.
I have a USB-C to USB-C cable from my iMac to my first display, (Samsung S60UA 24" QHD) and a DisplayPort cable connecting that display (via DP out) to the third display. I know the Samsung display puts out DP 1.2
What's odd is the third display mirrors the second display perfectly fine (both are QHD) but my Displays settings in system preferences does not recognize the daisy chain display at all. Of the two settings available (MST & SST), only SST produces any connectivity, though mirrored. Based on my research, this is the newer protocol anyway.
Thanks for any help in advance.
iMac 21.5″ 4K, macOS 12.6