In terms of Miami-Dade, it's not just Cubans who are right-leaning, but also Chileans, Colombians, and Venezuelans (the left-leaning Hispanic groups are mostly Mexicans and Puerto Ricans). Additionally, in Hialeah (a city with a high concentration of Cubans), the share of people with higher education is also relatively low (about 20%), which is another factor contributing to its rightward lean.
I think educational polarization doesn't work the same for recent Latin American immigration. The quite educated (55% bach) city of Doral, which is heavily Venezuelan, has moved about the same as Hialeah.
This makes sense in the context of Latin American politics. In the US, education is not really the driving factor itself in educational polarization, it's that educational attainment is correlated with trust in institutions. As the GOP becomes more anti-institution, people who trust them will go turn to Dems. This explains the military becoming more Democratic even though it's lower educational attainment.
In Latin America, and specifically for Venezuela, distrust in institutions could be right-coded again. The regime is left-wing and those who align with the regime, like major media institutions, are left-wing. However, relatively educated and wealthy people are right wing, and therefore being educated correlates with distrust in institutions.
Therefore, when the GOP bangs on its anti-institution and anti-left drum, it might be drawing in educated Latin Americans just as much as less educated Latin Americans. In more established communities, American educational polarization takes effect, which can be seen in Kendall, Pinecrest, Coral Gables, etc., which are all quite Latino, educated, and less foreign born.
