Which email providers have built-in encryption at rest ?

Hi All, still trying to figure out which email to go for. Thank you for the previous helpful posts. I am wondering which email providers have built-in encryption at rest ? I know that tutanota e protonmail (body and attachments for the latter) do it. It seems that Posteo does it, but needs to be activarted if I am not mistaken. Any other providers have it? Can't find the answer re: Mailbox Thank you