Both of those Nikon lenses are kit glass, so they’re going to be 3.5-5.6 or so… dynamic across the focal range. 3.5 at the wide end and 5.6 at the long end - give or take a stop, but I’m pretty sure that’s accurate.

Not ideal for a concert really but if they (op) stretches the ISO out and manages to get the exposure without running the shutter down too slow, might end up with a few keepers.

As a photographer… it would truly hurt my heart if someone didn’t continue to view at least some of my work after I’m gone. I hope that the images outlast me.