Let's talk encrypted email.
I've had ProtonMail for quite a while. It works well. The free tier only includes 500 MB, so you have to watch your mailbox size.
I recently set up an account with https://dismail.de , a one-man operation. I highly recommend it.
PROS:
It scores a higher than Proton in a few categories.
https://dismail.de/serverlist.html
Dismail gives you 2 GB. There is no paid tier, but Stefan accepts donations.
You can use your email client of choice.
1/2
^
XMPP chat with OMEMO encryption is included, as well as a few other neat services.
CONS:
Email setup is an extra step. Your initial account gets you XMPP chat, then you chat with Stefan and he activates your email, which had a different password.
No dedicated mobile app like Proton, but you can use any other client supporting TLS 1.2. I am (ironically) using Gmail right now. You can also use the webmail interface.
As I said, it's a one-man operation, but CoSo users probably don't mind.