I work in Stockton, and am glad that some people are better off with this. My real worry about UBI 'at scale' is what would prevent the majority voting for massive increases in the amount every election? If every employee could vote to increase "everybody's" pay equally, why wouldn't they? - right up until the company runs out of money and all the jobs disappear.
If you think that high income people generally don't produce enough value to justify their income, then you would probably consider this a feature, not a bug. Otherwise, I worry that it would just lead to highly productive people moving to other parts of the world, as happened with [British musicians in the 60's](https://ultimateclassicrock.com/rock-bands-taxes/). Again, if you think those people don't produce enough value, it's not a problem. But we might want to consider trying it successfully in a single state first before rolling it out more widely.