I agree with your view on source code, but the rest of this is over complicating something that airgapped hardware signers already do well. I don't think something like a nostr:nprofile1qqs09jtvjlmyrxjn37zv70a89csegcz7rpyqjmnw29cveedhv7vagqqpz4mhxue69uhk2er9dchxummnw3ezumrpdejqz9rhwden5te0wfjkccte9ejxzmt4wvhxjmcpzpmhxue69uhkummnw3ezuamfdejs92xe5k is any less trustworthy if you build it yourself. It doesn't even bother with saving your keys. You can be as paranoid as you wish with it though. I think is far more suitable than trying to use methods with an even larger attack surface.