Duales is the best way to go for sending money infrequently to Cuba. They can either deposit it to a Transcard or local bank pickup.
If you expect to be sending money regularly, then Transcard Smart Transfer is probably the way to go. Requires some setup. You deposit monery into YOUR ST account, then distribute it to card holders, using the Internet. At the point of transfer is when they charge their fees.
At one time, they issued the actual debit card to foreigners but stopped a few years ago. Card holders, at the time, were granfathered in, so they didn’t lose their cards. Now, they will only issue a Transcard to a Cuban.