I can vouch for this as I am the only east coast employee on my west coast team at AWS and I also have no expectation of moving to west coast or returning to office. I have spoken to managers on other teams around Amazon and flexibility is entirely dependent on your director/VP (the manager 1-2 levels above your group manager).

If you’re considering an offer from Amazon I suggest you make it very clear from the start to your hiring manager your expectations on remote work and working hours. Theres some teams at Amazon that are taking a strong return to office stance and others like mine that allow for fully remote.