UBI doesn’t give any power to those who own the means of automation, nor does it take power away from laborers. Automation does that. Automation reduces the leverage of the laborer by reducing the capitalist’s reliance on labor.

We have the same leverage regardless of whether we have UBI or not, but the leverage of employers is reduced with UBI. That said, if more people opt not to work thanks to UBI, then the people who choose to work will see their leverage increased.