The difficulty with Mars is latency. You get opportunities to go there every 26 months and then spend 6-9 months in transit. If you need spare parts you could be waiting for years. You want all the technology you depend on to be completely boring.
Notably the Starship system takes at least 12x the launches to put a payload into deep space than it takes to put a payload into LEO.
With those economics it might sense to build large structures in LEO, such as a flashy space hotel or a simulated lunar or martian environment patterned after a very small O'Neill colony -- recent research seems to show people can tolerate a higher rotation rate than O'Neill thought so a small Bernal sphere made entirely from terrestrial materials looks possible.