Personally, I'm not entirely opposed to UBI, but what I'd rather see is a system of guaranteed jobs and educational/training stipends (with part-time and/or remote options). The reason for that is primarily fault tolerance: in the event that a major disaster renders our AI/computational infrastructure inoperable (or adversarial), it's imperative that humanity itself act as a redundant store of all the information necessary to preserve or reboot civilization.

That being said, I do think UBI (with some guardrails) is still preferable to making everyone consume services provided exclusively by government monopolies. Not because anything provided by the government in particular is going to be magically low-quality, but because any monopoly is inherently insulated from long-term systemic incentives to compete on price and quality.