If I had to lean on my brakes all day doing an uplift somewhere steep, I’d be looking at brakes which were powerful, reliable and easily repaired.
I know that SRAM stuff is apparently very good these days and that Shimano’s standards have slipped a little, but I too had endless problems trying to get Avid brakes running right. I’d probably go for Hope if it were me.
I have previous generation XT on one of my bikes, which has been superb for best part of five years. My other bike has brand new Hope E4s, but previously I’ve been a happy Hope customer for almost fifteen years. Despite the horrible brake fluid, they’re a doddle to fettle.