Many countries have a form of UBI, although it's not guaranteed as the meaning of UBI would in a sense, but look at France with their RSA as an example, if you have no incomes/low incomes, you are entitled to it.
Where will this ubi money come from when there is no one to tax and profits are going to tech firms based in America.
RSA is not UBI, UBI literally means Universal Basic Income, it's not for no income/low income people, it's universal.
You are conflating the concept of UBI with social welfare, they are different things and it's a bit annoying to see the erosion of the UBI concept into social welfare, I've noticed an uptick of this the past year or so, no idea where it's originating from...