from recent posts
https://bitcoin.stackexchange.com/questions/88237/is-there-a-reason-to-why-bitcoin-core-does-not-implement-bip39/88244#88244and older posts -
https://bitcointalk.org/index.php?topic=812894.msg10907427#msg10907427 (Gregg Maxwell comment "Effectively BIP39 is a thinly veiled brainwallet scheme with a woefully weak KDF. It's prone to misuse, and when misused it picks up all the bad properties you might expect it to pick up.)
I am concerned about using Trezor, Ledger, Cold Card etc, regarding issues of PBKDF2. I believe that the seed is not adequate if I understand Greg Maxwell's comment..
I would love direction from Greg Maxwell or other Core devs what method of cold storage is reasonable for security but not prone to significant error. Further one that provides reasonable redundancy for multiple locations.
Copying Private keys by hand for dozens of addresses seems a less than ideal way of securing value with out making substantial mistakes.
Someone suggested ZFEC for encrypton by Zooko, however that project seems to not be well maintained or still alive.
I have looked at the glacier protocol and Armory however, Bitcoin Armory is not well maintained and Glacier appears quite difficult.
But maybe that is the route one ought to take.
I am not a dev, as must be pretty obvious by now.
I would love some advice on is "best practices."And where might I find documentation for complete directions.
Thank you very much for your help.