Here is an idea for @elonmusk and three of his companies. Create a hybrid of the launch power of the Tesla Plaid car, utilizing Hyperloop technology with the Space X Starship rocket. I know what you are thinking. How would you do that? Hear me out and I will explain.
Railgun powered rocket
I realize that this is not a new idea. NASA supposedly has come up with this idea, but Elon owns 3 companies that could combine their skill-sets and pull this off! Basically, you would install a rail, I mean a really long rail, possibly a 2 mile long rail. You would angle it at 30 degrees. Utilize electro-magnetic propulsion to slowly increase the forward motion to a max of 3 g’s. I would imagine that lighting the Raptor engines prior to energizing the rail would be best to be sure that they all fire. Once the rail system energizes, slowly increase the throttle on the Raptor engines so that by the time the Starship hits the end of the rail, it has been released from it’s carriage and has enough velocity to continue it’s flight.
Less LOX, more payload
Utilizing this method, you could put more resources towards payload and less to propellant therefore making a shorter spacecraft due to the propellant/payload ratio being lowered.
It is worth exploring, and who better at utilizing resources that are at hand than the Space X, Hyperloop, Tesla team!