I used to advise people to go work for an existing company for a few years before trying to start their own, but I now think that was bad advice. It's true that you learn things working for a big company, but you learn more, faster, starting your own. A lot of people we've funded have said they wished they'd quit their corporate job sooner. I don't remember any saying they wished they'd stayed in it longer. The one p…
It was hard. But I learned a lot (and made some mistakes). The problem? It was a small company, and there was no depth. There are limits to how far you can go on your own generally speaking. (in particular if the company is not expanding/hiring)
I never really got into the business side of things, but something similar applies. If you want to learn a lot about how business is done, you're going to have to get in on the very early stages, getting your hands dirty, curating customers, and seeing how/participating in how the business plan is put together.