Apparently, center-right from European optics, not very different than typical center-right parties like the German CDU/CDS - from an American perspective, he would be a Democrat.
While he was a member of different leftwing organizations when he was young, he is a billionaire now, and he proposes breaking with the economic model that the ruling party, MAS, has been applying for the last 20 years under its presidents Evo Morales and Luis Arce. I haven't been able to find any kind of outrageous declarations from him, either about immigrants (which I presume are not an important problem in a poor country like Bolivia), abortion, trans and gay rights, or other of the usual boogiemen of the alt-right; rather, he seems quite moderate in his declarations.
Actually, opposition from more extreme right-wing candidates has tried to harm his campaign by saying that he approves gay marriage, or that he would alter the Bolivian Constitution (link in Spanish) to grant free abortion - abortion is legal under rape, incest, or health risks. Medina has denied wanting to change anything related to abortion, while he has espoused views favorable to acknowledge social rights towards same-sex couples (link in Spanish), such as granting inheritances, nursing sick-days to attend a partner and such, even stopping short of legalizing gay marriage. So he seems quite progressive in social issues, especially for a country where even the left is quite conservative, being a quite religious country.
He has mentioned Trump and Milei (link in Spanish) in his interviews, but only to say that he plans to talk with everybody Bolivia can make deals with (so, he plans to disalign Bolivia with the China-Iran-Russia axis he feels they have been placed in), but also he says he plans to open Bolivia to foreign investors. Bolivia has extensive mineral resources, including some of the largest reserves of lithium, critical for making electric batteries, so China is definitely interested, and Medina says he's willing to talk with them.
“Nosotros no vamos a idealizar las relaciones”, lanzó. “Con los países que podamos tener un intercambio, un beneficio, vamos a tener relaciones”, recalcó, mencionando a Estados Unidos, China, Rusia y la Unión Europea.
("We're not going to idealize relationships", he proclaimed. "With those countries we can have trade, some profit, we're going to establish relationships", he emphasized, mentioning the USA, China, Russia, and the EU.)
Similarly, his only reference to Milei is that he has managed to cut Argentina's crippling deficit, and he plans to do the same. Bolivia is running a 10%+ deficit that is endangering the country's prospects. Leaving it to run amok, it could lead to a disastrous hyperinflation explosion, and Medina says, "you have to act fast in that kind of crisis". So, while he is a pro-private business, pro-foreign investments, and he has said he's going to dismantle several state businesses, he looks like your average economy-focused rightwing politician. Currently, scarcity of products, including fuel, is the first and foremost concern of Bolivians, and Medina is leaning heavily on the local economy policy so that he does not hemorrhage too many voters from the right on conservative social issues.