You can if the service doesn't handle encryption with a proprietary protocol and instead helps you set up PGP. It certainly has its issues and limitations, but

You can if the service doesn't handle encryption with a proprietary protocol and instead helps you set up PGP. It certainly has its issues and limitations, but after trying ProtonMail/Tutanota/what-have-you, I have _never_ actually used their E2E encryption except when contacting support for that mail service. Meanwhile with PGP I can post up my public key on my personal sites / resume / social accounts, and people actually have reached out. I also like that you don't even need to include your email address to prevent scrapers from harvesting it. If it's on one of the public keyservers, their client will find the email address for the respective public key.