So where is the question?

I think there are flaws and oversimplifications in that statement even before taking into account the planetary boundaries and international development dynamics...

Basically the state can invest without causing inflation by printing money as long as it leads to activating productivity and not to competing with other consumers for goods and services which are at their limits already.

Btw I am not a macro economist by trade the mmt just makes the most sense in comparison to other (neoliberal or classic) models