My dream job is CTO / founder at a tech company. I've attempted a few ideas but nothing's taken off so I'm trying to do the next best thing in someone else's company.
If you want to be a founder, it only makes sense to surround yourself with other brilliant people you can build with. Managing any team is beneficial for the resume, and that doesn't matter much if you're dedicated to building your own company. I'd recommend whichever option you believe empowers you to innovate; while giving you the flexibility to understand the context/foundation to successfully running your own business.