Isn't the whole point of UBI that it isn't progressive, but rather universal? Otherwise, it's essentially just another form of progressive income tax, where the bottom of the scale is a negative income tax. Right?
Well UBI is going to be funded by a progressive income tax regardless. We can toss "Universal" around all we like but the reality is that the rich are going to net lose and the poor will net win.
The universal part just means there's not much process associated with it, you just get the payment.