This seems wrong to me based on my understanding but i'd be willing to be educated.
Based on the fact that everyone got their money back from FDIC in what way have these bank failures caused "Cayman sandwich are getting broken by bank failures like svb"
The Cayman's had one purpose for most hedge funds. Move assets off shore so all gains would be tax free. Once you want your money you onshore it again in and pay tax on that total. This allows your money to grow tax free, which means if you're good at it, it grows faster.
It's just like a tax free retirement account that lets you deduct your contributes but makes you pay tax on the money you withdraw.
As far as for companies using the cayman sandwich, what i've read says everyone got their assets out, no?