Maybe I missed an update but: For whatever reason, IFT-4 is not planning to attempt in-orbit relight of the main engines. That means that IFT-5 must be put on a suborbital trajectory in case in-orbit relight doesn’t work. Starlink sats can raise orbit slowly, but don’t have the thrust to circularize their own orbit. (I guess one can imagine some sort of dummy sats to test the deployment mechanism, but I don’t think dummy sats should count.) See 7% chance of IFT-5 achieving orbit: https://manifold.markets/RyanTyznar/by-which-flight-of-starship-will-it