I haven't thought this through, but I don't see how you could have UBI without universal healthcare. If the point of UBI is to ensure the most basic necessities are covered, and "basic necessities" includes healthcare, and healthcare is the Luigi-inducing travesty it is in the US right now, how is it UBI without universal healthcare?
The alternative is that UBI is high enough to cover healthcare, which is extremely (maybe unfeasibly so) expensive and creates all kinds of other incentives for abuse. Or we fix the systemic, profit motive-driven problems in the current system by nationalizing healthcare.
Yes, nationalized healthcare is also problematic, but I think UBI will indirectly alleviate a lot of the systemic problems there as well.