First, I am not sure why you delve into the issue of taxes (consumption tax specifically) when discussing UBI. Using the moral evaluation of consumption tax to create some parallel moral argument with regards to UBI doesn't work in your thesis. It's literally irrelevant.

It can be argued that a UBI is actually superior to traditional welfare programs because it would be less bureaucratic to manage. It could literally be done via the IRS or treasury disbursements similar to what we saw during Covid with the Covid relief checks. Additionally, a UBI would supplant a myriad of welfare type programs from unemployment systems to food stamps. You cite this argument yourself.

Also,UBI doesn't need to improve on work incentives. That is a made-up metric. If UBI merely matched current incentives that would be just as acceptable. I

As to the cost- we have the money. Worrying about the tax rate and acquiring the funding is old-school economics which have less relevance to our modern economy than Modern Monetary Theory (MMT) which holds that as a currency ISSUER, the government cannot run out of money.

Finally, I don't get the title of the essay. How is it a "liberal" case"