Now that I've changed my email provider to one that isn't proton, and set up end-to-end encryption in #Thunderbird I honestly would highly recommend Thunderbird. It's the first time I've used it in many years. The UI looks modern, and it makes it super obvious if you're actually getting E2EE. It also automates key sharing and key lookup.
This is all built-in btw. No extension needed, it just does OpenPGP as standard.
Proton mail never actually did this in a way I was satisfied with. Now I actually know if the email I'm sending is going to be encrypted before I send it.
I might start adding a little message to the end of any unencrypted mail I send explaining that I was unable to find a suitable encryption key, see if I can subtly encourage people to start setting up E2EE. 
Oh btw Thunderbird works with Gmail and so you can stop Google reading your emails by setting this up. (People and websites will continue to send you unencrypted messages though, those ones they could still read)
@SierraKomodo@lexbailey What email provider are you using now?
@SierraKomodo I'm using Migadu, following the recommendation of a bunch of people here. It was a good recommendation, they have a very reasonable pricing structure :)
@lexbailey I switched from Proton to Migadu which lets me have a catch all email and I can send emails easily as any address on my domain. It's my first time using Thunderbird too and it's really nice.
@lexbailey We are so glad to hear that you're having such a great experience, especially with E2EE. And your idea for a reminder message at the bottom of unencrypted messages is pretty brilliant. 