What you are describing is very different from UBI. With UBI everyone gets a certain amount no matter what. There is nothing universal about what you are describing.
I don’t get how this follows, at all.
I like how you distinguish between the people who are eligible and the people who have applied, because some eligible people do not know they are and therefore do not apply.
It is brought up in the press [1] from time to time, and the percentage in France is somewhere between 40% and 50% of the eligible people, which is huge!
[1] in French: https://www.leparisien.fr/economie/votre-argent/aides-social...
But if you do, it's about £3.5k a year each I think. Not a lot of money. Certainly not enough to live on for a basic standard of living in our society.