I think CPI is a poor measure, because it's a moving meter stick that understates inflation. When beef is overpriced, hamburger switches into the basket. When hamburger is a luxury, then chicken swaps into it instead. It understates inflation.

M2 change is a much better measure in my opinion. Using M2 is literally comparing supply of item to supply of cash which could immediately buy it. When scaling SPX or GC1! by M2SL[0]/M2SL, you get a surprisingly flat time series over decades, which reads to me that the effects of the change in M2 are being filtered out of an otherwise exponential price curve.