At least in band photos you can use the moody lighting for your advantage and also grain from the high ISO only adds to the rock and roll.
I really suck at using a flash ”on the go” but obviously flash could have been helpful for something like this. I couldn’t even consider that because I knew I had to carry all my gear and overnight stuff on me all day so anything extra was left behing. No ”just in case I need it” gear 😅