I do not quite understand where the problem emerges, my only guess is that there is some I2C conflict? The light sensor becomes unusable after calling ArduinoCloud.begin(). This is surprising because I imagine the light sensor is something a lot of IoT folks want to use with Arduino cloud.
Does the NINA module takeover I2C in some manner? carrier.Env seems to be fine (temperature and humidity).
I did not. I got as far as looking into all the other I2C addresses used with the IoT hardware and didn't find any that might conflict with the light sensor. I had to give up on the IoT altogether for now because of how it's threaded: I have a motor control system that can't just stop whenever IoT has an issue.