AFAIK, they're not limiting imports. They are heavily embargoed since 1960s, which also affects other countries' abilities to trade with them, under the threat of themselves being sanctioned.
I went to Cuba, and they were a good amount of Kia Picanto, Daewoo and cars from China brands I could not recognize. Of course they can't import from the US due to the embargo, and Europe would be unreliable for after-sell service.
They trade, limited by their own poverty, with countries that can't be easily bullied by the US.
An embargo is an externally imposed limit on imports.
Doing it to to yourself is a special sort of stupid.
The only embargo is from the US.
Canada and the EU trade fine with Cuba. Spain alone accounts for 20% of the trade.
In fact, both EU and Canada have regulations that prosecute any European and Canadian company that complies with foreign embargoes (Council Regulation (EC) No 2271/96 for Europe and Foreign Extraterritorial Measures Act for Canada).
Of course US can pull its gigantic economic and financial levers to out-out specific companies to choose "you either sell here, but don't sell in country X" like it has done with ASML, but it can only push so much.
US laws apply to US citizens and companies.