My story is almost the same as yours. Contacted out of the blue by a couple of FAANG (maybe after referrals from acquaintances, but not even sure), despite having little experience (started my career in academia). Took me a couple of attempts over the span of a few years.

Interestingly, first attempt at one of them, they said I was ok for IC4, but wouldn't hire me at that level with my seniority. I'm also glad I eventually started at senior level rather than staff (and I'm happy to stay at that level too).