Savings accounts and mutual funds do not guarantee return. Also, there’s no such thing as mutual fund ratings unless it’s from a group like Morningstar that acknowledges the expense ratio is a better indication of rate of return than their own ratings.
There are money market mutual funds that are composed of 90%+ of US treasury bonds and considered as safe as FDIC accounts. These accounts are currently earning 5%+. They track with the federal reserve rate movements. Review money market mutual funds from Fidelity and Vanguard as a start. Note that the 7-day SEC yield numbers are after any fees. Good luck in your learning.