Imagine the Nazis with their enigma machine, and the cryptographer tells you, look, you have to trust this black box that is inside, it was given to me by a third party and I don't know how it works, I have to trust its specifications, our encryption security depends on it.

In cryptography you cannot depend on the trust of a third party, otherwise what is the point of cryptography?

You can spin it as much as you want to try to sell your crappy product but no security agency would trust these security schemes, in fact these security schemes are used to attack the enemy through backdoors (bugs), you have many examples like TPM, Intel ME, PSP, Dual_EC_DRBG, Apple T2, Google Titan, Qualcomm TrustZone, etc, do you think that your cheap chip (secure element) of your hardware wallet protects you?