Like I said, that would be you using BIP340 Schnorr. If you don’t need counterparties to decrypt your message, that is definitely sufficient over PGP. Timestamping doesn’t need PGP, you’re right.

We’re working on a standalone Schnorr library in Go that aligns with BIP340 standards for #Nostr. Will release soon! You can use it easily since Go works on any OS. If interested, I’ll expedite its release and link ya!