MMT'ers act like they've discovered some new concept. MMT is not economics; its political spin, propaganda, down playing the harsh realities of economics (not just "late stage capitalism" or whatever the kids call resource constraints nowadays.)
Government is a source of money. Taxation is a sink. Too much money in the system you get inflation, not enough deflation.
When you can print money taxation is just a way of controlling the amount of money in the economy almost by definition because you don't need tax to fund yourself when you can create money. Bonds just provide a stable financial instrument rather than a source of funding because you can literally just print money if you wanted to.
The constraint on money is mainly inflation, and government debt and tax is used to control the money supply.
That's it.
MMT is an elaborate way of describing the process of taxing investment capital away from existing capitalists such that the state can invest it itself. You may complain that the state would invest that capital poorly (others would counter that private VCs already do it poorly), but the essential economics of it is dead simple.