The end result is storing 24 english words. You can store them on paper, on a CD, an NFC tag, a stone tablet. Storing words long term is a well understood problem.
Do not trust any or this software to generate those words truly randomly? No problem. Use bip39 diceware to literally generate your words with dice.
When it comes to not trusting software to convert those words to a keypair deterministically, use NASA dual path tactics.
Use two unrelated software suites to convert those words to keypairs and sign a transaction and ensure the final signed payload output from both unrelated toolchains is identical. Bip39 has been implemented in many programming languages.
Now you can form strong confidence in your entire supply chain from key generation entropy to a final transaction with perhaps a couple hours of effort. If you are moving millions in value and worried about supply chain attacks the extra effort may be worth it.
For most a Trezor or a Ledger used as the instructions that come with it advise will be in fine shape.
How many people on earth would even understand what you just said? It's limited to a (probably small) subset of software experts. For the vast majority of people it's basically "trust the shady nerds and the VCs backing them".
Do not trust any or this software to generate those words truly randomly? No problem. Use bip39 diceware to literally generate your words with dice.
When it comes to not trusting software to convert those words to a keypair deterministically, use NASA dual path tactics.
Use two unrelated software suites to convert those words to keypairs and sign a transaction and ensure the final signed payload output from both unrelated toolchains is identical. Bip39 has been implemented in many programming languages.
Now you can form strong confidence in your entire supply chain from key generation entropy to a final transaction with perhaps a couple hours of effort. If you are moving millions in value and worried about supply chain attacks the extra effort may be worth it.
For most a Trezor or a Ledger used as the instructions that come with it advise will be in fine shape.