JanSport backpacks. My wife had the zipper wear out on the backpack she has had for ~20 years. She contacted the manufacturer. They don’t make that particular bag anymore so they just sent her a comparable equivalent with almost no questions asked.
The one I got has metal gears. They are the main point of frustration. They don’t really make a full rotation without getting bound/jammed up. Slow, fast, or somewhere in-between, it always felt like I was fighting to get the only moving parts to move.
I’ve no problem with simple. I like simple. For me, this thing isn’t simple, it’s frustrating.
Maybe I just got a bad one. A lot of people seem to have an appreciation for it that matches yours. I’d be inclined to exchange it for a different one. Sadly, Amazon refuses to accept it as a returnable item.