I have heard that the US goes after expats over this rule
This is not the case for act 20 / 22 / 60.
it is true that the US government is one of only 2 countries globally that tax their citizens for internationally-sourced income (the other is … Eritrea.). However, all of your income can be taxed at 4% under an act 60 export services company if it is structured correctly.
internationally-sourced income over $100k is taxed at normal rates for american citizens, even if they are living abroad. However, with act 60 this is not the case since it is a territory with special incentives. Act 20 /22 / 60 decree holders have a contract with the government that exempts/ them from paying federal taxes as long as they meet certain requirements.
there is no other way to retain your US citizenship and enjoy such low tax rates. Do achieve those rates outside of act 60, you would need to rescind your citizenship and suffer the corresponding treatment in the US (stay limits, visa requirements, etc)