Right so why would you do anything difficult like the hard labor required to maintain infrastructure?

Because you need/want more than $10k/year to live on?

The only thing that changes is that, with UBI, nobody is forced to work in degrading conditions so they can feed their children.

It's absolutely not going to work if you can afford children without working. Literally zero people will do anything they don't absolutely feel like doing under that social regime.

No country can run entirely on charity.

Then society will figure out a way around that - either by paying better, offering better job conditions, or automating the work away.

Instead of thinking about the toilet cleaners we’ll lose, think about the poets and physicists we are missing because they need to clean toilets.