Greetings fellow chicken.
I believe that if your cash is at a credit union, it's not covered by the FDIC. More likely it's covered by the NCUA, which I believe offers $100K per account, whether joint or not.
And, FWIW, I try to stay at or under the insurance limit. My cash is spread across 5 different brokerage accounts, 1 bank, 1 credit union, and one corporate MM. The brokerage houses typically have high insurance limits, but they may have a different limit for cash. The corporate MM is with Ford, which offers no insurance, but they pay 2.8%.
I used to live in Orange County, CA. Home of the savings and loan crisis and the largest municipal bankruptcy in history.