NEET payments, despite the name, are direct redistributive payments to everybody in society, funded entirely through a value added tax on all goods and services which replaces all existing social programs.

Instead of deciding what social services people receive, people should be able to choose what their social payments are spent on. This both increases the amount of value people receive through reducing bureaucratic losses and empowers people by increasing their economic freedom.

The regressive nature of taxes are a concern if you are worried poorer people will not actually receive the benefits from the tax, which is impossible given the money is directly redistributed without allocation. Richer people consume more on an absolute basis and will therefore contribute more than poorer people.

Yes, which is why in down-turns (deflation), the government should print money into NEET-payments to maintain a small inflation rate on the currency.