The sample of 2000 people were chosen from a group of unemployed people. I think the criteria for being randomly chosen was having been paid unemployment benefits during some range of dates.
So it's not representative of a real UBI at all: the point of UBI isn't to necessarily make things better for the unemployed but, rather, the large group of people who make very little money and barely get along.
Cashiers, cleaners, etc who can't live on their earnings, at least in big cities. Or self-employed one-person shops whose income stream is very choppy and who don't make much anyway. Real UBI would be universal so those who are working would get it too -- of course the UBI would increase your income and likely your tax percentage so it would mostly be taxed away from those who do earn a living.
The point of UBI is to cut down on bureucracy by removing various individual case-by-case subsidies (but bureaucrats would never vote for that) and make some base level of income predictable and reliable, mostly for people who make less than the lower middle class.