@slumberingcat Unfortunately, most if not all encrypting email clients are complicated to use, and few of them have a strong focus on making encryption easy. Vcards are currently the best interoperability bet, and at least ProtonMail should produce and ingest interoperable VCards. We haven't tested that lately, though. Providers: many work quite easily but they often have rate limits and anti-spam measures, and so relays on e.g. https://chatmail.at/relays are the easier choice.