In the library I wrote this post for, the encryption and mac keys are separate, with both the keys being randomly generated, and then persisted to disk encrypte

In the library I wrote this post for, the encryption and mac keys are separate, with both the keys being randomly generated, and then persisted to disk encrypted with an argon2 produced key (with some tertiary validation), which is what I generally recommend. The use of Blake3 as the mac _should_ avoid most of the problem with using a key that's derived from a password, but I very much like not leaving that door open.