Isn’t Fidelity FDIC insured?
Fidelity is insured through Lloyd’s of London, among other vendors. You pay for that insurance as a customer. There is no reason a company with infrastructure based on different technology could not also purchase insurance.
Crypto - no way to know what, if any, company is legit. If I use a hardware wallet and lose it I'm screwed. FTX seemed pretty legit a few weeks ago, they even had an NBA arena named after them! There are dozens of ways an unsophisticated investor can lose everything.