I'm a fan of UBI, but...
There's a good chance that if we had it, the level would be too low for disabled people and they would need additional top ups. (Tim Worstall was in favour of it---although the price of accepting it was abolishing the minimum wage---but he set the level much lower than the current disabilities benefits.)
We already have an age-based guaranteed basic income. The qualifying age is moving up because the rich won't pay for it we can't afford it. The level is pretty close to poverty, too.
Much of what you outline is problems with the benefits system. We could simply fix these problems.
Scroungers are vastly overestimated. And so what? Do we really care if people want to lounge around all day getting drunk? Because a system that can prevent free riders is a system so intrusive and authoritarian that no-one would want to live under it. And much of the problem with the benefit system is we are halfway down that road.
Biting the hand that feeds IT
