Crazy theory: most posts here are from German Tax office. They give a "free" advice, and send a fat tax penalty 5 years latter! Suprise: you never left!

Who's the German equivalent of the American Certified Public Accountant?

Those shouldn't be prohibitively expensive; even small businesses in the US can typically afford one. Just go ask them.

I would say not with tax law anywhere. It is very complex and has all sorts of interactions between things - e.g. double tax treaties.

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.

I'm not saying use it blindly. But it helps going into discussions with experts, advisers, etc. with some preparation and knowledge. Worst case you are wrong and they'll correct you and best case you pre-empt some actual problems. And it's not like advisers, accountants, etc. don't make mistakes, overlook stuff, or sometimes work against your interests. It helps being a bit hands on. And LLMs make that a lot easier.

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.