What's more secure?
100% of your XBT in a 2 of 3 multisig all 24 words seeds w/ 3 unique 128 bit passphrases for each cosigner (assume everything done right wrt pure randomness, backups, privacy, all of it)
or Single sig but dividing your stack into 20 wallets, all unique 24 word seedphrases, all with unique 128 bit passphrases. Again assume all done above board.