A direct, fixed cash transfer will never, ever have the properties you suggest. It's sort of the point of money that people can allocate it according to their priorities. You'll have a hard time stopping someone from taking a 100 fewer sqft apartment in exchange for a smartphone. Or colluding with the landlord to kick back part of the rent reimbursement in exchange for a smaller apartment.
To get what you're talking about, the government would have to directly issue housing, food, and clothes, or run another one of its extremely complicated and unintended-consequence-laden means-testing systems to tailor the amount of cash transferred for your exact situation a moment-to-moment basis, if it wishes to give you exactly enough cash to buy the things on your list and no others.
Once it's playing this game, you've lost the small government/simplicity/low overhead aspect which caused many to favor UBI over the existing welfare state. A UBI like you suggest is really not UBI, it's just government-issued basic necessities, an idea with substantially less traction.