2-of-3 threshold multisig backup:

backup1: seed1, pass2, e(D, pass3)

backup2: seed2, pass3, e(D, pass1)

backup3: seed3, pass1, e(D, pass2)

D is the descriptor e is an encryption (could be just 7zip, but strong KDF wouldn't hurt)

would be nice if a multisig wallet supported this out of box.