UBI is generally proposed as a basic sustenance income, a fairly austere lifestyle that is “enough” but likely not fulfilling.

Of course if you don’t have enough “work” to go around, that vision of UBI becomes pretty dystopian, as some people are stuck with bare bones living with zero opportunity for better. If we do get there, then that sort UBI isn’t going to be enough, but as you say it it’s too much and you still need human work some, well, is a tough question…