So literally a solution in search of a problem. A living income guarantee has my blessing, but UBI doesn't. It's either too low, and there's still need for welfare, unemployment benefit, etc., or so high that the (unpredictable) consequences can completely overwhelm the advantages.
That's a strong claim. What makes you think so?
If UBI becomes too high, people will stop working, inflation will rise, and there won't be a safety net of subsidies and welfare left to help. So if e.g. the price of housing rises, the UBI will be eaten up more and more by rent and mortgage, and people with only UBI will be as poor as before, and people will be forced into very low paying jobs.
Furthermore, I've never seen a convincing source of funding for UBI; at the first sight of an economic crisis, UBI will be lowered. At that point, there's no way to revert the UBI, leading to a new poverty trap.
And reality is going to be wilder than my imagination.
If the problem you're fighting is poverty, then provide welfare for poor people, stimulate work for them, make schools accessible (in backwards countries where that isn't the case), etc., but don't try to restructure society. That's just ego.