Why would my 401(k) investments in Money Markets perform a lot worse than my simple savings account with <popular online bank>? Looking for a simple solution to modest returns.

It seems to me that a "money market" would consist of known guaranteed things like savings accounts, so I'd expect my 401(k) money market fund to be somewhere CLOSE to my savings account, but since Jan 1, it's given me +0.9%. My savings account is 4x that. What kind of funds should you pick if you're looking for 3 to 5% return?

I'm not looking for "stock market is typically 12% over time" etc. I'm looking to make 4% on my 401(k) money for exactly 2 more years then I'm off grid. Seems like that'd be doable since <popular online bank> can do it with guaranteed results!!

Three years ago, I could have taken out all of my 401(k) money, taken the tax hit, put the money in a few different popular online banks (for FDIC reasons), and been BETTER OFF today! (I'm old enough to not take the penalty). Am I THAT BAD at picking investments, or have I been dealt shitty products?