What makes you think bonds are stable? Vanguard's Total Bond Market Fund is down 8.03% in the past 3 months / 10.54% in the past year.

In regards to risk adjustment you can change your investments / asset allocation.

Target Date Funds do this automatically, otherwise you can manually move the investments. You'd only want to do this in retirement accounts or else you'll pay taxes on moving the money though.

If you mean buying actual bonds, that is a good method to mitigate risk, but most people can't do that in a retirement account.

Some bonds are, Hungarian government-backed bonds pay 6% guaranteed yield yearly. Been going strong for years even with covid and such. It is the textbook 'risk-free asset' from the Black-Scholes formula. Of course it's been a much better investment when their inflation was lower than that :) It actually blows my mind how much of financial modeling ignores taxes and inflation.

They're not as stable as cash, but more stable than stocks. I wasn't giving precise recommendation here, just commenting on how the people usually deal with the risk when getting close to the retirement. Similar to the target date funds, but at least in Australia I can do similar moves manually.