In effect, we have the "benefit" of a Universal Basic Income now, though not an actual UBI. It takes the form of a government guaranteed safety net. If you lose your job, you get unemployment. If your unemployment runs out, you get welfare. Everyone gets a check, but they have to either work for it or show that they are unable to work for it. Enforcement of the requirement is pretty lax, but you have to go through the motions.
No one is starving and homeless in the U.S. due to lack of available funds. The homeless in the United States are universally addicts and mental patients. Neither is forced off the streets and into treatment by the U.S. government as is done in other countries. That's why we have homeless in numbers unseen in other first world countries.
In third world socialist countries you do see homeless and they are homeless because they are too poor to afford both housing and food, and their government is unable or unwilling to help them. It's a mistake not to see the economic difference between the two.
But replacing or supplementing welfare with a non-needs based UBI would be a big mistake. Money will lose its value if everyone gets a significant amount of it every month for doing absolutely nothing but being part of the Universe.
So I can explain what I mean, what amount per month did you have in mind for a universal income, in today's dollars?