Wasn't FTX considered a reputable custodian before it imploded? That's been my understanding but I didn't pay much attention before it went belly up.
True custodial banks could in fact be fraudulent for allow e know. But they don't buy super bowl ads to buy reputation -- they've earned it over the course of decades.
Real banking should be boring.
I would compare FTX to say Tastyworks. Clean brand, but they're not a bank, not insured, and not focused on custody, so it wouldn't really be prudent to store idle cash or crypto with them.