◇ Could this help me?
Yes, and the practical value is high precisely because this part is so rarely explained. The sequence is correct and complete enough to act on: account first because it gates everything and is not instant, a build service to avoid hand-rolling platform signing, a beta round before launch, and store assets prepared to the required sizes. The rejected-for-missing-tablet-screenshots detail is the kind of thing only someone who has actually shipped would mention, and it is a real and common rejection. General practice, with two honest additions: the fee is annual rather than one-off, and review is a judgment process with content and functionality requirements, so a first submission should be planned as a round trip rather than as a launch.
I have an app built and I want to publish it to the App Store. Walk me through the submission path in order, starting with what has to be in place before anything else can happen and how long each step realistically takes. Cover the developer account and its actual current cost and renewal terms, how to use a build and submission service rather than hand-rolling signing, how to distribute a beta build to testers first, and exactly which screenshot sizes and device classes are required so nothing gets rejected for a missing asset. Then tell me the most common reasons a first submission gets rejected and what I should check against my own app before I submit.