My father retired several years ago and took his entire 401k and put it in a bank IRA CD earning 6% or so. It expired after 5 years and he was getting offers of less than 1% for a new CD term. He asked for help and I tried to steer him to closed end bond funds and blue chips stocks but his number 1 (really only) criteria was "it can't EVER go down. It is everything I worked all my life for."
With that dictate, all I could do was find him an insurance annuity that was RMD compliant. We got him 3.30%. He has an option to reset the rate upward once if market conditions permit. I should maybe have him check current rates. The entire term expires at year 7 and he has to be about halfway through that. Even 3.5% would move the needle for him.
For most people, an annuity is a poor choice. But for the hyper conservative investor, they are the only game in town.