@nicfab @Fr333k Email crypto is extremely complex and because of this, has plenty of attack surface. We published close to 10 papers in the last seven years attacking email and email encryption with OpenPGP and S/MIME.
I am at the point where I find recommending email encryption to be actively harmful. Metadata leaks all over the place, crypto from the '90s, plaintext fallbacks everywhere, user hate it, in particular the gnupg devs are very toxic, mail client developers lack time and (too often) expertise to implement it properly.
Just use Signal. If you got budget, build an app on top of Signal. Heck, just use WhatsApp. Just don't even try to send sensitive information with email encryption.