6
I have one through AMEX for about 6 years now and haven’t had any issues, I’m at a 3.5% APY
SoFi.
SoFi is what I use and I love it
Ally is pretty good imo.
Wealthfront seems to be good currently 4% also has other options for investing / savings
It doesn’t matter too much. Open a HYSA wherever you do your banking.