The government should provide for a base level of food, medicine, housing, and education.
But let private industry compete for it, so just provide vouchers for each of those things.
But, how to efficiently allocate the amounts for each individual? How much health care voucher vs. food voucher vs. housing voucher vs. education voucher?
Ah, just have a universal “health or food or housing or education” voucher!
Oh, but what about transportation!
Okay, a universal “housing, food, medicine, transportation, and education” voucher.
Oh wait, we have one of those already! The dollar.
If targeted programs can be poorly designed or mismanaged inconsistently, then so could UBI. The whole idea is to thoughtfully design a program. If that is possible, there's no reason we can't thoughtfully design targeted programs, and UBI would still be there in a lesser capacity precisely for those people that would fall through the cracks of those targeted programs.
UBI just feels like a kind of sledgehammer, when a dozen scalpels might perform better. I'll grant that UBI would be superior to the very loose "safety net" of social programs in the US though.
Even with a "strong" UBI program, I still think we'd need other programs as well-- UBI will be far too low for people that suddenly lose a job that pays 5x UBI and need to get by until they find new comparable employment, as an example.
If you suddenly lose a well-paying job, food and housing still cost the same for everyone, which you can afford on UBI, by design.
You'll have to give up the expensive lifestyle afforded by the lost job, of course. Maybe move to cheaper housing. So what?