Citizens of Saudi Arabia get a cut of the country's oil revenue. That was fine and grand until the bottom dropped out of oil prices. They have a very large swath of people that live on money from the government and have very few skills otherwise.
What UBI will do is let more employers pay minimum wage. Where employees were getting £400/week, new hires will start at £300/week. That's great for Zuckerberg and Musk. Elon built an auto manufacturing plant in an area with some of the highest cost of living figures in the US and Zuckerberg operates a company that produces nothing.
People that slept through math and economics will see UBI as a boost in income, but will be blind to the tax increases that will shortly follow to gobble up that money. The people that educate themselves and work hard to earn a good salary will start re-locating to the first country that creates a low-tax environment for more than the very wealthy. Lots of Soviets were more than willing to get the hell out of the USSR and didn't care what country crest was stamped on the front of their new passport. This is the same as raising the minimum wage artificially until robot burger flippers and ordering kiosks become very cheap in comparison to low skill labor.