I tried to film fireworks with the M30T 2 miles away but the video only shows black & white. Pretty sure it is something basicand elementary in the camera settings (it was on auto). What did I do wrong?

I'd say you used the Night Vision improved photo mode ( don't remember exact name ), M30T isn't a "photography" tool. You have to check the focus, Aperture and ISO. Probably the shutter speed too.
ps: https://www.nikonusa.com/en/learn-and-explore/a/tips-and-techniques/taking-pictures-of-fireworks.html#:~:text=Set%20the%20camera%20to%20a,for%20the%20entire%20fireworks%20burst.

AR_AirPrecision Posted at 7-10 02:40
I'd say you used the Night Vision improved photo mode ( don't remember exact name ), M30T isn't a "photography" tool. You have to check the focus, Aperture and ISO. Probably the shutter speed too.
ps: https://www.nikonusa.com/en/learn-and-explore/a/tips-and-techniques/taking-pictures-of-fireworks.html#:~:text=Set%20the%20camera%20to%20a,for%20the%20entire%20fireworks%20burst.

Thanks. Should have stuck to my P4P.