What’s the best student loan refinance option right now for getting the lowest interest rate?

I’m trying to lower my student loan interest and monthly payments if possible.

I’ve got both federal and private loans and I’m looking into refinancing since my income and credit score are better now than when I first took them out. Just want something with a lower rate but still some flexibility in case things change later.

I’ve looked around a bit but the rates seem different everywhere.

What’s the best student loan refinance option right now for getting the lowest interest rate, and anything I should be careful about before I switch?