livePreview is not designed for streaming. It is designed to supply a preview of the image scene before a picture is taken.
If you use it for streaming, you will have lower resolution or lower framerate.
Most people put the THETA Z1 on a robot with a USB cable attached to a Jetson Nano or a Raspberry Pi and then use the small computer to transmit the stream.
The Amelia drone project did use motionJPEG livePreview.
