HYSA vs Brokerage Fidelity Index - which to choose?

Hello 👋

What exactly is the philosophy of HYSA versus index funds in my brokerage account?

I have about a mid-five figure savings that I am reviewing. I do not have ability to invest in retirement accounts at the moment. So it’s those two other options above.

I also have no plans to spend any large amount of money in the next several years but I may need several months of living expenses to access whenever I can in case of emergency.

Maybe half-and-half? Cheers