I'll have a look at the data sheet. Thank you. I'm very new to using SE so it's going to take some figuring out.
Here's the schnorr sigs nostr stuff
https://github.com/nostr-protocol/nips/blob/master/01.md#events-and-signatures
The DS28C36 is NIST P256 too? https://www.analog.com/media/en/technical-documentation/data-sheets/ds28c36.pdf
(This link above btw is an abridged data sheet. The full datasheet is under NDA for which I call bullshit. Friends don't let friends use Maxim.)
The Koblitz curve is really exotic outside the blockchain/nostr bubble. Nostr doesn't use Schnorr sigs AFAIK just plain EcDsa.
Not sure how Coldcard works.
Discussion
Schnorr sigs indeed not sure where I had the idea about EcDsa from. That's even more exotic then. The NXP SE050 would to Koblitz curves in some configurations but just EcDsa not Schnorr. Good luck finding an SE that can do that.