I was hired to add a subscription and publish. The code was the part I controlled. App Store Connect was empty. The privacy policy was a file. Products were half-finished. That is not a Swift problem.
What I cannot invent
Tax forms, a public privacy URL, screenshots of a product I do not own, display names the client has not written. 5.1.1 and incomplete IAP metadata were those gaps with guideline numbers.
What I ask for on day one
Access to App Store Connect, or a named person who will complete Agreements, Tax, and Banking. A hosted privacy URL. Product copy. I would rather wait on that than debug StoreKit for an unsigned agreement.
Hangar was easier because I was the client
First-try approval was ownership, not luck. When I take a Fiverr-style store job now, the listing is in the quote. The eight-rejection story is still the warning: first submission.