It depends on your project, and a single number quoted without your specifics would mislead you.
Three kinds of work set the date: what you configure, what you build, if anything, and what you test. Beyond that, the biggest influences are your platform, your carriers, who holds your carrier credentials, whether your wider stack is changing, and how your team is resourced.
For Transport specifically, carrier credentials are a hard gate: nothing can be booked without them, and there is no reduced mode to launch with. Releasing them early is the single most effective thing you can do to protect your date.
See What shapes your timeline for the straightforward case and the case that needs more planning, and Carrier credentials for what we need per module.