tcb22:
I started backpacking in 1958. I currently own ten backpacks and have worn out, discarded or given away half a dozen more.
My current go to backpack for multi-day trips is an Osprey Aether 85, which costs $310 at REI. I also own an Osprey Exposure 66, which I use as a larger daypack. Both packs have the same suspension system and it is the most comfortable system that I have worn.
The cheaper your gear is, the tougher you have to be. I've aged beyond the tough stage.
KC