The best case I described would move wealth from landlords, through the middle class, to the poor and middle class. It would accomplish that by both expanding and devaluing the middle class. Expanding the middle class would eliminate poverty (no more poor category). Devaluing the middle class would shrink the housing market (not enough high-paying renters to sustain runaway rent growth). Shrinking the housing market would move wealth from property owners back to middle-class income, which is exactly where it came from in the first place.

The primary method that the poor and middle class are exploited by the rich is housing. The benefit of middle class life is captured by rent and mortgages; then moved into the portfolio of wealthy real estate owners. If we can put that in reverse, we all win.

Ideally, UBI would move wealth back from real estate portfolios back into wages and disposable income. The middle class would be less wealthy on paper, but have more disposable income from not spending it on housing.

It's not as elegant as directly stealing from the rich and giving to the poor, but that doesn't seem possible anyway.