Running a business in Germany is for a closed inner circle. The apparatus is not meant for broke college students turning their weekend project into a company.
Now wherever that's an issue with the 25k admission fee OR with the fact that wages have stagnated for about 25 years in Germany, consequently mostly wiping out the middle class ... That's debatable.
German median household wealth is 4x that.
This estimate includes things like a car, a partially paid off house and other assets.
Most of that wealth cannot easily be converted to cash which you'd need to start a company.
Also that's median. Germany is a country with a median age of 45. So yeah, someone who likely worked for 20+ years will likely have saved around 100k, I don't think you realize how that's an argument in favor of what I just stated...
Filing insolvency must be done without undue delay (a special legal term) and no longer than 3 weeks after you have realized that you might be in insolvency. If you fail, you will be personally liable in full (though there is a honor codex amongst insolvency lawyers to not go after the family home) and you might face jail time. These rules and personal liability have actually been made much stricter in recent years as well.
Depends on your product and expectations of your customers.
B2C: I don't care what company structure you are.