The biggest set of data points comes from the most obvious and widespread UBI - the state pension. Available to a certain section of the population
That's how all UBIs thus far appear to work. You need a fixed exchange rate area where some people don't get the UBI so that the physical output that actually funds it can be extracted from the people who don't receive it. That separation can be physical area, or age.
We can see from the state pension that the majority of people in receipt of it don't work. Instead they live off the output of others.
If UBI was a realistic possibility then the age at which people receive the state pension would be heading down towards 18 (since a UBI is just a state pension where the qualification age is the age of majority). The data tells us that the qualification age for retirement pensions is heading upwards, due to a lack of productivity gains to support it.
We also see complaints about its existence, which demonstrate that the capital inheritance maintained by the older generation and handed over to the young is not seen as sufficient to justify the state pension payment given to the old. Capital hasn't been maintained well enough and doesn't give enough to younger people. To the extent that younger people are agitating to have the state pension reduced or removed.
Switch 'old' and 'young' for 'in area' and 'out of area' and you see why UBI 'experiments' always end or are ended. Those who end up working to create the material output that actually funds the transfer get fed up getting nothing material in return and have the transfer stopped.
Somebody has to do the work to grow the carrots. If you aren't doing anything meaningful in return, (which means what the carrot grower wants you to do, not what you want to do) why won't they stop growing carrots when they have enough for themselves, and have Fridays off?