Marcus House has worked with several people to use detailed calculations to model the first SpaceX lunar missions. NASA has funded the development of a lunar Starship.
They have determined it will take about seven refueling missions to fully fuel a lunar Starship in Earth orbit. This would then have the fuel to go to the moon, land on the moon and take off from the moon to return astronauts.
Four more refuelings would be needed to give the Starship enough fuel to re-land on the moon from lunar orbit.