The GiveDirectly trial in progress now (been a few years) is the closest to what you're talking about - 20k people in 197 villages in Kenya getting a basic inco

The GiveDirectly trial in progress now (been a few years) is the closest to what you're talking about - 20k people in 197 villages in Kenya getting a basic income covered fully for 12 years. https://www.givedirectly.org/ubi-study/ https://www.givedirectly.org/ubi-study/