So I was able to figure out how to plug in an HDMI devices to an apple studio display... via purchasing some 3rd party adapters. The issue is that the Apple Studio display specifically looks for Thunderbolt 1st, then Display 1.4, which means you will need some adapters/special cables to get it working.
With this method, you will get full resolution support of the 5K Monitor, but will loose:
- Audio
- Camera/Microphone
- Brightness Controls (set on Mac before using)
- Cannot use rear facing USB-Hub on Apple Studio Display
To be able to plug in an HDMI Device; You will need:
- Bi-directional Display Port 1.4 to USB-C cable: Amazon
- HDMI 2.1 to DisplayPort 8K 60Hz Active Adapter: UTAB
Once you get these, just plug one end of the adapter into your HDMI device and the USB-C end into the back of the Apple Studio Display (The port that has Thunderbolt Icon on the back)