I think there's a danger in removing art from any kind of market mechanisms because it can lead to some very navel-gazing output that appeals to very few. In the long term, this kind of art would lead to making this kind of UBI unpopular and would undermine the whole thing. Not a lot of taxpayers are going to be on board with paying someone to can their own feces[1] or submerge religious icons in piss[2] for example.

[1] https://en.wikipedia.org/wiki/Artist%27s_Shit

[2] https://en.wikipedia.org/wiki/Piss_Christ