I still thing a lot of it transfers over, especially if Starship works as intended - send Starships to Mars often with proof of concept tech and any customer payloads & have part of it pressurized with prototype life support system. If it works fine after the trips on multiple occasions, you can be reasonably sure it will work with a crew as well.

Possibly more sure than the "classic" testing (and paperwork) heavy model that usually does very few actuall test flights due to costs.