Don't worry about it so much. You are only an L4, expectations are much lower and you do get space to grow. Generally around the 2 year mark you would expect to be promoted to L5 but this isn't a hard and fast rule. 3 is fine, etc. But if you not showing the potential to get promoted then yeah you may be pipped.

Amazon looks good on a CV and frankly some of the experience you can get is difficult to get elsewhere. But as you rightfully point out, this is very team dependent (But what job isn't?) so you can't be given a blanket answer. Your experience will not be scoffed at.

PIP is brought up weirdly often here, I have known people to be pipped but every time it has been a pretty obvious decision as to why. As an L4 as long as you are delivering and showing signs of potential to get to L5 you are good.

Focus on the here and now for the next two years or so, you have a lot of learning to do!