Colonizing mars is a stupid thing to do pretty much full stop.

Mars cannot be terraformed. It has no meaningful magnetic field. That’s a dead end for a planet’s ability to retain a useful atmosphere and ward off cosmic radiation. You’ll have to live in shielded, sealed pods to survive there, always. In which case you may as well be in space with access to abundant solar energy and less of a gravity well to contend with for your frequent resupply missions. There’s barely any advantage to being on Mars compared to orbiting some random Lagrange point or the sun itself. I guess you can make use of some earthworks for civil engineering? Hardly seems worth it.