Well my journey was a bit different than yours. I was Lead Dev at a small startup (<10 people) and went to a non-FAANG Fortune 500 and assumed a Sr role on a team. Things I didn't think would bother were a dress code. It does, it does bother me. Especially in the Summer. I was surprised on my first day that I didn't get to choose my own O.S. I really miss Linux, it really effects my productivity being in Mac. I thought projects Jira tasks would be better planned, they are not, they barely have any information in them. Documentation is a joke somehow. Onboarding was a joke. They just kinda stuck me in there. I couldn't believe I had better processes in place at the startup. Things move slow. Some days I barely have any work, its not much fun. There are things that can't be beat though. Chance to move around. Better benefits. With that said, I'll be looking for a smaller company after I've reached my year mark (they have me in relocation expense cuffs).

I hope your experience is better. If you're going to a FAANG I imagine it will be. This place is much more buttoned up.