My passport timeline:
09/29/2021: Applied for expedited adult first US passport at a local acceptance center
10/04/2021: US DOS received passport application
10/05/2021: Application status changed to ‘In Process’
11/01/2021: Application status changed to ‘Shipped’ with USPS priority express mail tracking number included, and estimated delivery date of on or around 11/04/2021
11/02/2021: Application status changed to ‘Approved’
11/03/2021: Passport delivered to my mailbox
Door-to-door time was exactly 5 weeks (35 days). Interestingly enough, my application status switched to “Approved” after “Shipped”, instead of the other way around, and stayed as “Approved” after delivery. The passport was shipped from Little Rock, AR and delivered a day before the estimated date on the application tracking site. Moreover, I learned that USPS reuses/recycles tracking numbers, hence when I initially tried tracking the delivery through USPS, it showed me old tracking information from 2019.
Hope this helps, and good luck everyone!