"one can look at history and wonder if the Cuban people would've been better off living in an American territory similar to Puerto Rico instead of [under Castro's rule]."
You might not agree it would be better for certain, but you definitely can at least imagine an American Cuba that's healthier than the current Cuba. It's not a particularly high bar.
In terms of social health (person to person), one can say that Cubans enjoy a better situation.
"Political health" is a debatable rathole, on the other hand.
The US has the highest documented incarceration rate in the world, and the largest prison population. (One in 31 adults in the US are under the supervision of the criminal justice system).
Their mortality rates are the same as the US, and the food they eat is a lot healthier out of necessity due to low industrialization.
If getting a medical degrees leaves you with no debt, and practicing as a doctor saddles you with little liability, why would you be able to demand a high salary?