Maduro convinced me, that's who. Specifically, Maduro's behavior in office for the last N years, and even more specifically, his behavior toward opposition parties. (Imagine Trump having Biden arrested in April 2020 on some transparently fake charges, so that Biden can't conduct a campaign. Trump wins the 2020 election, though there were "irregularities" in the vote. Then he dissolves Congress. Then in 2023, Trump arrests whoever the leading Democrat candidate is. Would that be authoritarian? I would say, absolutely yes.)
I think it's more interesting to ask, who convinced you that Maduro is not authoritarian? And, what possible evidence would change your mind?
The same opposition that illegally declared itself the government after losing an election? The one that attempted to smuggle US weaponry into the country under the guise of humanitarian aid? The one that attacked and killed poor black people in the streets? The one that bribed military personnel to betray the country? The one that welcomed a (thankfully incompetent) US coup attempt? It’s not like Guaido was arrested on the spot. He was free to continue breaking the law as due process was being followed.
Also worth considering the constant sanctions and threat of invasion by the US that Venezuela is subjected to. Of course capitalist-owned media will smear a revolution of poor, black and indigenous workers against the former slave owning colonisers.
I think it's more interesting to ask, who convinced you that Maduro is not authoritarian? And, what possible evidence would change your mind?