As a Miami native, I can tell you for a fact Cuban remittances do indeed happen. The sanctions loosened after the Obama admin d'tente even after the Trump admin restored most of the controls. My alma matter https://cri.fiu.edu/cuban-america/remittance/ has a continued focus of research to see how much flows go back to island nation.
Anyway tl;dr is that Cubans use: https://havanaship.net/nueva-agencia-de-remesas-a-cuba-orbit, which is a gov't controlled remittance operator. As of commenting isn't on the OFAC controlled entity list. It used to be sanctioned after the previous remittance operator was associated with the Cuban Army but is now in compliance.
Anyway tl;dr is that Cubans use: https://havanaship.net/nueva-agencia-de-remesas-a-cuba-orbit, which is a gov't controlled remittance operator. As of commenting isn't on the OFAC controlled entity list. It used to be sanctioned after the previous remittance operator was associated with the Cuban Army but is now in compliance.