I think UBI is a terrible idea. It would create a new class that has absolutely no power, since they provide no labor, and is completely dependent on the capitalist class generosity to survive. They would have a worse quality of life, then those on minimum wage or unemployment subsidy.
Reduced working hours is a necessity at this point. For the last hundred years there's been no improvement in working hours, despite productivity rising massively. It seems this struggle is abandoned. But maybe a 6 hour working day could relaunch it? Also, from a productivity perspective, we need to work less, because capitalism is destroying the planet by overproducing, at this point we really don't gain much by increasing production even more. Food is a great example of this, we already overproduce the amount of food we require to feed all the human population, it's a problem of distribution and waste.