As another European, it seems to me like you haven't given much attention to internal US politics. Trump has (at the very least) repeatedly questioned some foundational principles of democracy. I recommend you check out "Project 2025" - if this prospect doesn't make you worry about the political future of the most powerful nation on earth, then we have a fundamentally different understanding of what a healthy democracy looks like.

Democrats (and I don't mean the party) should be worried about Trump and what comes with him.