With public key, lookup id on keyserver, which should reveal email address.
use your own pgp to encrypt message to them, send in email
Discussion
Cool 😎. Thank you 👍
What is a key server? Where do I find it?
A keyserver is a server for storing, retrieving, searching PGP keys. There are several, but due to abuse over years many are defunct
Recommended reading for more understanding: https://www.rossde.com/PGP/pgp_keyserv.html
May be easier to use tools like Kleopatra to connect and do the lookup
Thank you 🙏