In 2013, Maduro was incredibly popular. Hell, in 2019 he was incredibly popular. So despite the fact that he felt it was critical to prevent the American-aligned party, who was actively calling for a US invasion, from taking power, he was still their by the will of the people for at least 8 of those 12 years.
The claims that Maduro was a dictator are primarily biased readings of a conflict between the US and the anti-imperialists in Venezuela. The US first started organizing regime change in Venezuela 25 years ago. The first attempt was staffed by Venezuelans, but funded, organized, trained, and facilitated by the US. The sanctions have killed tens of thousands of Venezuelans and driven poverty and hunger to levels of desperation. This is why there's been millions of emigres.
For 25 years the US has been sending covert operations staff to Venezuela, training people who would like to overturn the government against the will of the people, and when Maduro stepped into office he became part of that battle. His choice was to hunt the subversive elements in the country and purge them, with or without murder. Even at the worst estimates of his body count, which are based entirely on speculative evidence and just sort of guessing based on satellite imagery and interviews with poor hungry people (who will say anything for safe passage and food for their kids), he has some far less violence than the US has to Venezuela in the same time frame.
This is not a choice between a dictator and a US intervention. These are interrelated processes. The crack down on dissent is a result of the president of Venezuela securing the country against US subversion. If the US wasn't subverting, the president wouldn't be cracking down. We know this because it happens in the run up to nearly all historical regime changes run by the US. Iran under Mossadegh also nationalized the oil fields, just like Chavez, and he was also popular, just like Chavez, but when the US and UK started building the operations for the coup, Mossadegh had to find them and stop them. If he didn't, they would harm the Iranian people. He spent a couple years getting more and more draconian on his attempts to find the spies and subversives and purge them. And he lost in the end.
Maduro was not wrong that there were literally US spies and special ops all over the country. He was not wrong that the opposition party was working with them. He was not wrong that they were trying to harm the Venezuelan people for money and power. But he failed to stop them.
So now we're left with the question - should he have purged harder, or should have done it differently? And the only way you can answer that question is if you understand what the government of Venezuela was doing for the last 25 years since Chavez first took office. You need to know how they were working to prevent this sort of outcome, what things they did implement, and then you need to study what other governments have implemented and whether Maduro could have done it differently.
And at that point you'll hopefully be humble enough to realize that you're Monday-morning-quarterbacking running a fucking country when you're up against a US regime change operation and that you really have no ground to stand on to critique Maduro as a dictator who needed to be stopped for the good of his people.