You are right, I have a more advanced version
The Theta part is the same. I’m using Theta V, I will probably switch to Z1 in a near future.
Theta is connected in usb and all works with gphoto2 (with a modification in the source code to get the shutterspeed working). There is no live streaming, it takes either photos or videos. I change the RaspberryPi 3b+ with a raspberryPi 4, downloading content from the Theta to the Pi is about 10 times faster. I didn’t have tested the UVC driver yet because I want to keep the original mp4 stream without decoding and mainly because this solution is working fine (live streaming is done with a “standard” low-light usb webcam)