Given the amount of intellectual effort you have so obviously put into the issue of money and the economy, I am hoping you might be open to an alternative I have developed that is neither MMT or a UBI. If it matters, I do have an M.A. in economics.
My proposal is a DDI: “democratically distributed income.” It would be paid to eligible citizens; the total of that income would be the supply of money (as currency) for the economy. While it would not be paid to everyone, or even all adults, it would be available for an unlimited number of people. As I see it, the amount of the income should be based on the current median income, so in the U.S. today, say, $15/hr.; $600/wk.; $31,200/yr.
One criterion of eligibility would be adult citizens who were willing but unable to work. That would include people were were incapacitated, permanently or temporarily — as in sick or injured. It could also include people who were unable to work due to a natural disaster, such as a pandemic.
Unemployment and poverty would be absolutely, positively eliminated. The same process could be used to fund government (all government, from central to local), eliminating the need for taxes/public debt.
To prevent inflation money would have to be returned to its point of origin (either the existing central bank or a newly created Monetary Agency). However, people and businesses could retain plenty of money (based on income/profits) and, unlike taxes, no money would be collected before it could be used (at least once) for purchases/investment.
If curious, a place to start would be “A Truly Great Idea,” published in Data Driven Investor here in Medium. also in Medium: “Re-thinking the Economy’s ‘Fuel System’” “A Call for a (Further) Central Bank Revolution” “A Cure for the Ills of Capitalism”