Tuta is the closets to Proton ID you’re looking for just strictly email. Otherwise I’d suggest Fastmail. But also depends what you’re looking for in the provider. I went with fastmail as they help develop open-standards such as jmap instead of imap. They also to encrypt all data at rest and own all their own hardware. This was what sold it for me at least. Good luck 👍
Tuta is the closets to Proton ID you’re looking for just strictly email. Otherwise I’d suggest Fastmail. But also depends what you’re looking for in the provider. I went with fastmail as they help develop open-standards such as jmap instead of imap. They also to encrypt all data at rest and own all their own hardware. This was what sold it for me at least. Good luck 👍