Thank you for your reply.
I can express myself badly. I wasn’t talking about having two video streams at the same time.
Currently, to shoot with a GoPro Hero8, I use a Firefly Split 4 camera for video feedback. The GoPro only records and is not used for video feedback.
The Firefly Split4 camera is one of the few small cameras with a micro HDMI output, but the video link is unreliable. To overcome this I am using the VGA output of the camera and added a VGA to HDMI converter to have a more reliable video link, but that is a lot of electronics to add to have a reliable video link.
So I wanted to know if you would consider offering a simple 100% Herelink compatible FPV camera ?