On live music photography…
Like most opportunities it’s situationally dependent, but consider-
Do you have full access to the band and the venue?
Work with band before the show.
Is the act hard rock or something mellow?
Size of venue?
Are you with the band/house and is the band expecting pro results?
I use a 24-105mm and a 200mm fixed. Maybe a 600mm from the back of the hall. I find switching lenses much a distraction.

I’ve used Domke Camera straps and camera bags personally and professionally since they came out. I don’t hang a strap around my neck but go over the shoulder. The cotton straps are easy on the shoulder and last. I use them with with DSLR’s, camera bags and pro audio gear.

I go native camera format. If I’m shooting for broadcast or just like the look, that’s 16x9.
There are a number of different formats - like Cinema at 1.85:1. Rolliflex twin lens reflex cameras use a square format. Medium format can be 6x7cm.

When I fly with still or video gear I use Domke wrap and then in a Pelican case with foam. I carry on that Pelican and put it overhead above my seat if. Everything else is in Pelican cases and is checked & insured luggage.

Tv has been in 16x9 format since the introduction of digital broadcast.
If have a 4x3 Tv..... odds are you don’t watch much content on 4x3 TV.

I shoot 16x9 or requested Cine format for Broadcast since we went Digital.