And in my jurisdiction, after I took a two year training school on my nickel, then work 7500 hours as an apprentice at slightly over minimum wage, then did the extra stuff to be a contractor… you'd be able to.

The requirements seem extreme, though I did break a fan blade in my indoor air handler while checking its temperature, total noob mistake. If I were hiring a trusted contractor I'd want someone better than me!

Ideally there might be room for a grade of lightly trained technician which can handle the easy stuff and do some of the time consuming diagnostics then just throw in the towel and say "You need a better man than I."