If the choice is between a comprehensive welfare state/UBI for both citizens and non-citizens, with restricted immigration vs. welfare/UBI restrict to citizens

If the choice is between a comprehensive welfare state/UBI for both citizens and non-citizens, with restricted immigration vs. welfare/UBI restrict to citizens only but with more permissive immigration, I suspect the vast majority of non-Americans would choose the second. UBI for non-citizens is nice, but completely useless if the US won't even let you in. For people in poorer countries, the quality of life improvement from coming in the US would be so drastic, that preventing people from making that movement, simply to give a small minority of them a marginal benefit, seems to be the wrong decision to take. Another way to put it is that the two tier system already exists, it's just that the second tier is outside the US/developed countries.