The funding for UBI would require more funding than the current federal tax revenue. One of the things that would be necessary to make it work is redistribution of wealth. Taking taxes large corporates who are increasingly making more money through automation and the removal of jobs, so that it can be used to fund a better lifestyle for the majority of people.
Sadly I don't see a political environment where that's actually viable any time soon, but at some point we're going to have to see a move in that direction because there will be an ever decreasing pool of jobs that require actual people.
The cost of UBI depends entirely on the magnitude of the benefit; your position is indefensible given we haven't established the magnitude.
Obviously increasing welfare implies increased taxes. I don't see anything controversial there? I do agree the USA currently lacks the political will to move much in this direction.
Sadly I don't see a political environment where that's actually viable any time soon, but at some point we're going to have to see a move in that direction because there will be an ever decreasing pool of jobs that require actual people.