They just make it very hard to complain. And it always is necessary to do a lot of back and forth

It probably varies based on item price and how obvious the issue is. I had two sub-$10 items arrive visibly broken recently and got refunds in under 5 minutes.

They're more likely to only give a few dollars back rather than a full refund

You have to call their bluff when they try to pull that, they don't want you to ship stuff back either. I got a full refund after a few back and forths of "are you sure you want to ship that back for a refund??".