So what happens if Bitcoin ETF gets hacked/loses seed?

Looking to invest in Bitcoin ETF but have something on my mind:

Say for example Fidelity, who owns their own Bitcoin, loses their seed, gets hacked, whatever. What would happen? Would everyone who owns the ETF be screwed? I understand their security and ability to keep a seed phrase safe is much greater than my own, but I'm wary of putting in my hard-earned retirement money into something that could be lost so easily. I'm pretty sure it wouldn't be insured because of how much money that would be gone.

Does anyone know what would happen in an event like this?