I'm going to keep this really short. There a lot of posts here giving you some amazing tips and tricks for Amazon interviews, so I would recommend you check that out if you haven't already.

The recruiter actually reached out to me in December, but I responded and subsequently took online assessement in March.

Online Assesment :

1. Similar to this - https://leetcode.com/problems/k-closest-points-to-origin/
2. Similar to this - https://leetcode.com/problems/rotting-oranges/

After I cleared the assessement, I was directly called for onsite(virtual). I initially had scheduled it for beginning of April, but then rescheduled to start of May as I was very busy with work and couldn't concentrate on Leetcode.

Onsite:
( For the behavioral part I got all questions from this list - https://tinyurl.com/shx4mf8 )
1st round : similar to 3-sum with a lot of followups.
2nd round: Object Oriented Design - Design Vending Machine.
3rd round: calculate mean, median and variance in a running stream of numbers.
4th round: https://leetcode.com/problems/sliding-window-maximum/

Recruited reached out to me after 4 days to tell that I made it to the offer stage.

Some simple tips which I've found useful:

1. For LP, since you'll have virtual onsite for Amazon, writing up some important keywords on sticky notes for all the stories you've made and pasting on the side of your monitor helps a lot. It'll give you O(1) lookup time(as it'll be like less than 20). As Dan Croiter said its perfectly fine to do that.
2. Speaking of Dan Croiter, try to watch few of his videos on youtube to get an idea on how to answer using STAR etc. Some of the examples he gives should suffice.
3. Practice some OOD and system design too. Doing just LC can only get you so far.

Good luck!