I agree that the media is lazy and makes these comparisons willy nilly. Trump, Bosonaro and Duterte don't line up completely but they put them all in the same basket.
However, Milei himself is trying to draw attention to his favorable views of these presidents. The article I linked to was a Milei quote about how he had a natural alliance with them. He wrote a book with Trump center on the cover, not sure what he said about Trump in the book though. He went out of his way to comment that the election was stolen from Trump, only something hardcore Trump partisans believe.
This is not to say they are the same. Trump is more like a right wing K. Protectionist, blames outside forces for troubles in the country, populists, calls media fake news, drums up conspiracy theories about the elites trying to take him down, etc.
I agree; to me Bolsonaro, Trump, and Milei all go in the same basket because they choose to put themselves in the same basket. And of course they all ride on the Evangelical/online youth/anti-science/ImGonnaBeRichSomeday/throw-the-bums-out vote...
It would be shocking if the random grab-bag of things supported by The Right in one country was supported by The Right in a different country; why should anti-abortion/pro-gun/anti-science/traditionalists support one trade policy over another? Or, why would views on protectionist tariffs pair with a certain stance on publicly-funded dental care? Or unisex bathrooms?
Itś like some spooky political entanglement that political parties hang together, even in one country.