And what do you actually use? I know the answer is probably self-hosting but maybe there are other solutions for a decent privacy.
If you want to self host, I recommend mailcow. It is not that hard to install and if you follow the instructions you’ll have a working solution whose mails are not considered spam by every other sane server. Sadly, some operate with whitelists.
I have looked at it and its system requirements are just insane. No way it would run on my cheap 1 GB VPS. I use a script for setting everything up, but less because I want to (I was warned about complications) and more because I cannot afford a second subscription.
6GB of RAM is for up to 8 concurrent users.
A privacy email provider and email aliases for everything you sign up for.
Email Providers
Protonmail
Tutanota
Email Alias Providers
Simplelogin
addy
Proton pass does e-mail aliases if you pay up for the high tier subscription
But its though SimpleLogin, not ProtonMail itself.