The spaceX plans for mars include putting a half-fueled starship in low earth orbit, and then launching 4-5 more consecutive starships to ferry fuel up to fill the tanks.

Problem is you need to burn fuel just to transport fuel into low Earth orbit, and kg for kg this kind of mission would use more fuel overall than a single large rocket. Would not even be practical without reusable rockets

Ofc no rocket is big enough to directly launch starship into Mars orbit so with current technology, this is the best solution - unless you wanted to use a smaller final stage