CTO as a startup cofounder and CTO of a large (100+) company are such different roles that they should really have different names.
If you're CTO because you co-founded the company or you joined at an early stage and you just happened to be the most senior engineer at the time, you really have no idea what being CTO of a large company is like.
If you're CTO because you co-founded the company or you joined at an early stage and you just happened to be the most senior engineer at the time, you really have no idea what being CTO of a large company is like.