Founding any form of limited company is expensive and complicated. Want to put a website online? Have fun putting your full name and address in the imprint. Want to offer some courses that teach X? Yeah, no, you need a license for that, mate!
Also being self-employed you lose most social benefits. You need to get private healthcare, you need to save up for retirement and so on. Getting back into public health care later on can be a bit complicated.
So my advice is to keep working part time on a job that gives you health insurance and everything and work on your company in your free time.
Germany is also one of the least friendly countries for expats. And I say that as a native Germain. Officials will refuse to speak English to you. Yes, refuse. Most people know how to speak English but often can't be arsed to do so. Plus general xenophobia and people being very tight-knit and not open to making new friends.
