To be honest: I keep hearing that PGP was / is difficult to use. That couldn‘t be further from the truth - but somehow it has become an urban myth. From the very first versions that I used on my first Mac up to GPG Mail or Proton Mail I never encountered any significant difficulties and could successfully exchange messages with my peers - both in business and private contexts.
I once had a chat with a security professor who had decided to try to get his group to use encrypted email for all of their communications. And they just couldn't get mailing lists working right with encrypted email.
Please, enlighten me on how you used PGP where calling it hard to use is so far from the truth. ProtonMail only works if you send messages to another ProtonMail user. It does not protect you when you email someone else.