It’s very misleading to say that “Cuba is keeping itself isolated”. Each year the UN votes to end the embargo/isolation imposed on Cuba by the US, with the vast majority of countries voting in favour of ending the blockade each time.
In the latest vote, in November, only Israel and USA voted against ending the blockade. Ukraine abstained. 187 member states voted in favour of ending the blockade
The US sees anything that could shake their narrative of the world as a threat, even when that ‘threat’ is unfounded, and they massively abuse their economic and military power around the globe to keep others in line.