Actually, you don't even have to quit. Just knowing that you can quit, if you're not happy, changes how you interact with your employer. Don't like what you're doing? Do something else, either there or at a different company.
I think if I KNEW this, I'd have a significantly different perspective on things.
Freelancing is hard. It's especially difficult to get into a part time situation. Most clients don't want a consultant, they want an employee they don't have to file HR paperwork for. But if you network enough, you'll get there and it will be fine.
I think, if you can get out of the soul-crushing chasm of despair that is wage employment, you'll find that software development is indeed your calling. You just don't like being treated like a child in that calling.