I don’t think there is any good way to test UBI at any small scale, I think there needs to be a critical mass of people who can pay their housing and food costs how society and economic activity would be reshaped under such a system.
Were the US Coronavirus payouts not a small-scale test of UBI in themselves?
What is interesting about the payouts is that we magically made the money for them while also magically making the money for a ton of other stuff. Obviously the scale of one time vs recurring is vastly different but I feel like this does go a ways towards proving its possible.