It looks like some color information is coming out in your renders, but everything is very dark. I saw you said you already changed setting exposure to Manual. Did you also adjust exposure compensation to bring up the exposure? Did you do this on the post process volume, or on an individual camera? Doing it on the PPV will affect all cameras (as long as a camera is not also overriding it - leave the settings on the camera on default to confirm.)
I set up a simple test scene on my end to confirm the Shot track with spawnable cameras doesn’t result in black frames, and that worked out correctly. It makes me think you are having an issue with exposure.