UBI kills the initiative and incentives of people who are productive.
The point of a UBI is to eliminate the perverse incentive to receive welfare rather than work, but the level of taxation that it demands creates an even larger perverse incentive not to work.
A fundamental economic principle is to add value through work. When income is given for free without work this does not add value to the economy.
If people want to— or already do — live in locations with higher standards of living they will work hard to get there. A UBI will not cover, only supplement, such high costs.
Productivity is not dependent on salary and compensation. Happy, healthy people are far, far more productive than miserable, yet well payed people.