I've used the same set-up (X-t30 and camlink 4k) and my guess as to why it shuts downs is due to overheating. I tried to tweak the settings to optimize for long calls but got at most around an hour of camera time before my system shuts itself down. I dropped the video to 1080p at the lowest possible frame and bit rates. Maybe it could last longer at a higher bit rate because the camera wouldn't have to compress in body, idk. The main point is that I think it's unavoidable that the system shuts off after some time due to heat. I wish there was a 720p setting because I think that would help a lot and video conferencing doesn't need full HD. That could squeeze some more time of of things for sure.