I've seen numerous posts about people getting Amazon New Grad SDE1 final interviews of either 3x45min or 1x30min, whether its in the USA or Canada. Moreover, it seems as though the 1x30min interview is significantly easier than the 3x45min interviews. From what I've read, the 1x30min interview is simply a code review of OA2 while the 3x45min interviews are a mix of behavioral and medium/hard leetcode questions for each interview.

Personally, I've completed OA1-100%, OA2-100% and I subjectively feel I did well on OA3. However, I was still selected for 3x45min interviews for Amazon Vancouver, Canada. This has got me wondering what are the selection criteria for being chosen for the 1x30min interview? I'm a new grad, with good grades, attending a mid-level tier university, and with mid-level tier internships. Do they tend to look at grades and big-n names for universities and internships?

I've also seen that OA3 performance can be a factor in selection for the 1x30min interview. Apart from going over the leadership principles in depth, is there any other guide or information that can help to ace OA3? I feel like there isn't any information on this and I'm sure a lot of people are wondering the same thing on how to get selected for a 1x30min interview.