> requires that I am able to regain access to my digital accounts using nothing but a few page paper backup including core service passwords & exported TOTP secrets.

EDIT: you basically save a 256 master seed as a list of 24 words (out of a fixed dictionary of precisely 2048 words, so 11 bits of entropy per number). 264 bits altogether: last word contains 3 bits par of the seed and 8 bits of checksum.

Trivial to write down. Very little chance of miswriting it for: a) you must prove to the HSM you wrote your seed down correctly and b) the dictionary is known and hardly any word can be mistaken for another.