Nice work. :)
Q: Do you plan to make keys available via gpg --search-keys?
FlowCrypt is GPG compatible in terms of exchanging email, but I don't plan on connecting it to GPG directly.
Most people don't have GPG installed or don't want the trouble of having to install it. Besides, I don't think chrome extensions have a way to interact with it directly anyway.
You can export the public keys from GPG using gpg --export --armor
After that, you can import it in FlowCrypt Settings -> Additional Settings -> Contacts -> Bulk Import