You would still be losing purchasing power due to inflation. At this scale it as long as you are not a greedy moneywhore investing it, or not would not impact a lavish and privileged lifestyle for a few generations.

If you wanted to keep your descendents wealthy for as long as possible, you park it all in a trust, have a family office manage it for you aiming for real returns of 3%, so roughly 5-6% nominal returns and descendents get whatever real returns acrue after inflation as income forever.