Thanks for the thoughtful breakdown, I think the isolated/autonomous Frost-shard generating device is a pretty interesting idea.
But coming back to relays, as far as I understand NIP-29 relays themselves have keypairs and can generate administrative events (I see now that Flotilla came to NIP 29 only later on so maybe not the best example for NIP 29, but regardless)
I also understand that the relay admin can also swap the relay's keys out. The relay would then need to update the group metadata to reflect the new public key, the update would then need to be disseminated, etc. So not the the relay URL is ultimately where the validity lies at the end of day, just as for a cashu mint.
At least that's how I *think* I understand it NIP 29 relays.
Could not this setup be tweaked to allow for relays with keypairs and that can publish actual notes in addition to administrative events? And if so, could these relays also not be surfaced by the likes of Jumble, once the parsing logic is there (check the metadata for the public key, etc.) Another NIP, but taking some inspiration from NIP 29.
That's the sort of companies-as-relays concept I'm squinting at.
Or am I missing something important here?