Elgato Cam Link 4K

The Cam Link has USB on one end and HDMI on the other.  It lets you stream and capture from your DSLR, mirrorless camera, camcorder, GoPro, or other devices with HDMI out.  However, do check the list of supported cameras.

This appears to be the cheapest 4K input solution available and it appears tolerable so we’ll take it.