You are indulging in a Black And White Fallacy here.

UBI doesn't mean no one works. It means no one has to work just to live.

And even if you want to ignore the actual scholarly research on the subject (which is ample), we have plenty of examples of people who would never have to work a day in their lives, and yet they still do so, sometimes even despite millions of people actively hating them for it: the very wealthy, particularly those who inherited generational wealth.