That's probably the very last spot where you want to use an LLM, especially not in Germany. One single mistake can cost you a fortune, and you won't be able to spot the mistake because you're not an expert. LLMs could be used to prime you for conversations with an expert (but be prepared to be corrected on points of law and fact) but they are no substitute. Corporate law is a legal minefield, tread with utmost care.
The whole proposition is in a way bizarre: if you have this problem you almost certainly can afford proper guidance and if you need to resort to an LLM for that guidance you almost certainly don't need such complex constructs in the first place!
That said, a lot more people would probably use complex constructs if they were not so expensive to set up because of the advice needed. I just do not think LLMs help.
Also LLMs are great for picking apart complex bureaucratic procedures, figuring out what next needs to be done, what the meaning is of some 10 page pile of crap the tax office dumped in your mail box, etc. Especially if you are not a native German speaker. You can ask your critical questions, get it to explain stuff you don't understand, etc. In the end, you are responsible for your actions. Limited liability in Germany isn't that limited. So, spending some time on figuring out whether you are doing it right is hard work. LLMs help.
But yeah, don't vibe run your private finances and sources of income.
Those shouldn't be prohibitively expensive; even small businesses in the US can typically afford one. Just go ask them.
Having an accountant is one of the hallmarks of a legitimate business.
If you're doing it on your own without a professional to watch out for you, and advise you, and take care of the details so you can do more important things, it isn't a company, it's a hobby.
That's where you hire a professional accountant. Which you should be doing anyway at the point where you raise any sort of external funding that's not family members.
I don't get why people are always complaining about German taxes. As long as you're small, you can just wing it. And when you pass the threshold, professionals are cheap.
Anyway, I call the German attitude to this topic Stockholm syndrome. The thing is, I've lived in four countries in the EU so I know how things can be different, more efficient, etc. When I say Germany is a PITA, that is relative to the Netherlands, Sweden, and Finland and based on my experience with those countries. Which isn't even that recent. Those countries were miles ahead of how things are in Germany today decades ago. And I wouldn't exactly refer to Finland and Sweden as tax havens.
Taxes are quite high here. Fun fact: when I moved to Germany from Finland, it was an internal transfer for Nokia. My salary was compensated up because of the higher tax and insurance cost in Germany. From Finland! Of course, the cost of living is quite a bit lower here. So this was a nice thing for me. But it's not a cheap country.
Doing this is standard practice if you are founding a company. You need to plan for your startup to be actually successful and being on the receiving end of a big exit. You can't just wing it and hope for the best.
Germany has a large amount of wealthy small investors, business owners, family owned businesses, etc. And many of those might retire in places like Spain, Italy, etc. There are ways. You just need to understand the system.
That's not to say that Germany is not a huge PITA when it comes to managing all these constructions, dealing with the bureaucracy, and the maze of silly government agencies that refuse to share even the most basic information with each other so you are stuck in ground hog day providing the same information over and over again (who are you, where do you live, what is your company registration, etc.). But once you know the how this backwards and dysfunctional system works, you can get it to work for you. Because painful as it is, the system does work more or less as advertised. But you do need to familiarize yourself.
BTW. this is a topic where LLMs can be helpful. You can skip a lot of the traditional advisers and other middle men, if you are a bit smart on that front. Using an accountant is actually worth the money for liability reasons. So don't skimp on that. But otherwise, knowing what you are getting into in terms of bureaucratic process can save a lot of time.