It is very unlikely that this guy (Javier Milei) will be voted President of Argentina in October. He has around ~25% support, but it is concentrated in certain areas (capital region and some other big cities), and also a lot of people oppose him fervourously.
The reason why it's difficult for him is that Argentina has a two-round presidential election system. It is not totally unrealistic that Milei arrives first place in the first round. There are two major party coalitions in Argentina currently: the Peronists or Frente de Todos (FdT) - current government -, and Juntos por el Cambio (JxC) with UCR and Pro - a center-right coalition, which led the government between 2015 and 2019. According to current polls Milei could aim to get a similar result to these two forces, e.g. all three getting around 25-30%, thus creating a three-party system.
But even if he arrives first or second in the first round, he has to win the second round ("ballotage") too. Here it's becoming complicated for him. He has better chances if he faces a candidate from the Peronists (FdT, current government), because then it could become a center-right vs center-left battle. But the Peronists are very strong in most provinces, so I'd give him around 30% to succeed in this constellation. It's also noteworthy that one of the possible Peronist candidates, current Minister of Economy Sergio Massa, is also a
Bitcoin supporter, but has more traditional views about economic thought.
It's very unlikely that Milei wins if he faces a Juntos por el Cambio candidate in the second round though, as JxC is much closer to the political center and would for sure attract also Peronist votes.
I quite agree with some of Milei's stances but not with everything, some of his ideas seem quite otherworldly and utopian (before his Bitcoin "love" he has advocated for an introduction of the US dollar in Argentina), and some even reactionary.