How do you hide the encryption key you use to encrypt the mnemonic?
Discussion
You disperse them geographically.
The difference is that you don't have to trust the trusted parties.
They can't see your balance.
They can't access the info.
They have no idea what's hidden behind the encryption.
They are laminated QR codes that require a password paired to unlock.
Uhm it seems that you are adding tremendous complexity to your setup, SSS is already considered too risky in general, this is even riskier.
Imagine you cannot access one piece, or that you forget one/x password.
It plugs into a very easy to follow inheritance plan.
You can duplicate the QR codes. You could have 10 distributed that unlock the same secret.