If there's tax progression, everyone's net income does not go up. That UBI money has to come from somewhere, and it comes from taxes. To fund the UBI, taxes will need to increase.

So at some threshold level of income, flicking the UBI switch doesn't affect your net income. You get a same size of increase to your tax bill as you gain from the UBI benefit.

Below the threshold you get a net increase, above it you get net decrease. Opinions differ on where that threshold would settle at (because with UBI the state could shut down some other benefits that are currently funded with tax money).