This is incorrect.

The actual cost of UBI is not simply the annual amount multiplied by the number of recipients, just like the actual cost of buying a $20 bill for $20 is not $20, but $0. The actual cost requires calculating the net amount transferred from top earners to middle and low income earners, and that calculation also requires taking into account the welfare reform and tax reform that UBI allows through by the replacement of various programs and tax credits with UBI. In the end, the real cost of UBI is somewhere around $300-$600 billion.

The net cost is lower BUT the government has to raise and redistribute 3.2 trillion, either by

Taxation — Raising taxes steeply across the board. Disincentivizing productivity and penalizing the productive.
Printing money— A lot of it! That causes inflammation raising the cost of living and you get into this perpetual game of having to raise the universal basic income to catch up with cost of living.

Another factor that these optimistic analysis ignore. The same political faction that wants UBI also wants limitless, unfiltered immigration.

Whenever the democrats or leftists get in power our borders become none-existent.
Illegal immigration is encourage instead of penalized.
Chain migration, birthright citizenship or the idiotic lottery migration flood our country with low quality migrants.
Liberals refuse to filter for migration based upon clear heuristics that indicate that certain migrants would integrate better and contribute more to our country; like education, IQ, professional skills, income, net worth, cultural compatibility, or language skills — No ingles, no problemo! UBI para todos!

We won’t just be paying $12k to every American adult, we’ll be paying $12k to every single adult human who likes free money capable of reaching to our borders, which is potentially billions of people. And we’ll be offering them a tremendous bribe of $12k/year to pack up their lives and come take advantage of our idiotically generous system.