There's multiple ways to include growth analysis, different KPI including household incomes, job numbers and over quality of life.

Government did not inject liquidity into the system, the banks do that. Government allows it. They also create stimulus injection which is poorly managed decision making rather than a failure of the system. It's called greed.

Purchasing power fluctuates constantly, it's the same as FX. It errodes but can also rise in value. See China for example of FX manipulation and undervalued Riminbi

Inflation is a "theft" when policy makers and bankers abuse low interest rate periods and 'stimulus' as a means to print money with no attributable GDP to go with it.

Inflation is actually good, it improves the overall goods and services as long as the right central bank policies are issued by the fiscal policy makers. This is a concept non-graduates do not understand.