Under this framework, what if you simply bribed people to vote for your candidate of choice: e.g. Here's 20 euro, vote for this guy.

You could still say "The people who voted for this guy have agency and decided for themselves."

But this doesn't really pass a smell test for what we want democracy to look like.

Similarly, if you live in a country and you see billions of dollars poured into your election advertisements from USA, Russia, China, etc, you'd be like "wtf are we even sovereign?"