yeah, inheritance with bitcoin is probably the only hard problem because of how it requires granting access to the secret keys of your UTXOs to someone somehow... i think stamped metal plates stored in a secret location with a key that you keep on you would work... then normally nobody can get at it but if you ded they will find it
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Multisig also can help with assisted custody or giving your loved ones a key each and keeping your keys in a variety of ways, like the solution you just said. Lots of schemes can be thought up.
It’s possible that within a decade your modest Bitcoin stack will be worth more than a payout under a life insurance policy.
You can beat the ‘returns’ on a life insurance policy … bonus: you don’t have to die!