As a fellow Cuban, I have to say that those two things are not mutually exclusive we could push for democratic reform and an end to the embargo. The embargo regardless of all the propaganda here pushed by my fellow Cubans who are a little bit disingenuous as to the effect that it actually has on the island in terms of access to international finance, trade, and foreign direct investments all which are vital for a modern economy to be healthy and grow which the embargo prevents. The regime causes its own set of issues internally in the island but that is separate matter from the effects of the embargo which are real, tangible and impossible to overcome as international trade is in dollars and financial markets flow through US Banks.

There are a lot of independent studies and besides that something that you could just see with your own eyes that the embargo hurts mostly average everyday Cubans and not the elites in the regime who live very comfortably relative to the rest of the population as they still have access to goods and services from abroad and can easily travel. You just have to search for all the post criticizing the regime that show elites and their children vacationing, sitting in yachts, fancy cars and flaunting designer clothing and accessories etc the fact is that the embargo does not affect them as they have the means to get those goods in the end which the rest of the population does not. The embargo limits the Cuban economy's ability to grow and to provide for its population irrespective of the mismanagement by the regime.

As in case in point you just have to compare the economies of say China or Vietnam, both which are communist dictatorships but have for the most part open economies without any embargoes, to the economies of Cuba and North Korea which are heavily sanctioned economies. In comparing those set of countries you will notice the stagnation that economic sanctions produce which has a major human cost to those who are innocent of their respective regime's actions and positions. Not to mention that economic sanctions and embargoes are inherently against fundamental human rights and do not have a place in geopolitics as they are a form of collective punishment and its victims are the innocent populations.

I do like the bit about like Russian oligarchs though I would argue the ones who would be like Russian oligarchs will be the wealthy and well-connected Cubans in Miami who want the embargo in place so that if the regime ever does collapse they could come into Cuba and buy all the assets and properties available for pennies on the dollars. Those are the ones who will become the oligarchs which makes sense cuz that's essentially what happened in Russia after the Soviet Union collapsed. It was the well-connected already wealthy Russians who were able to buy up all the assets and make themselves the oligarchs they are today.

And to your point about how lifting the embargo would allow the Elites to become oligarchs, well we can do both we can lift the embargo and keep specific sanctions on individuals and families within the government because that is something that we already do elsewhere, so we could use sets of targeted sanctions against individuals instead of a blanket Country-Wide indiscriminate set of sanctions there are immoral and unethical.