Monetary inflation is a nominal phenomenon. It's not the returns to investment that are changing (that is determined by the free market) it's just the returns to holding cash. It's the measuring stick for value that is changing.
You can still save and get real market returns through owning real private assets like stocks.
> It's not the returns to investment that are changing
How so? Quantitative easing controls the yield on bonds, and stock prices adjust accordingly to keep their yields consistent with the bond yield + risk premium. We've seen the earnings yields on stocks plummet as a result. After a short-term rapid climb (caused by the step change in interest rates), low interest rates can cause the long term growth of stocks and other assets to also remain depressed, even while consumer prices climb. This is the "stagflation" scenario and is a very real possibility.
You can still save and get real market returns through owning real private assets like stocks.