> This all started for me about three years ago, when I left a Google review for a doctor saying I felt discriminated against. Shortly after, I got slapped with a legal threat demanding €40,000 in damages. I ended up settling and paying €1,000 in legal fees just to avoid the nightmare of going to court. That was my wake-up call—but back then, I thought it was an edge case.

Sounds like you need an anti-slapp law[1], I did a quick google and it looks like one is in the works[2] but not implemented yet. Given your experience it seem unlikely anything is currently in place, of if there is it does not give much protection.

[1] https://en.wikipedia.org/wiki/Strategic_lawsuit_against_publ...

[2] https://www.blueprintforfreespeech.net/en/news/german-govern...