i personally use fastmail as they have a good privacy policy
but there’s still the problem that all my emails are stored on fastmails
servers so i can never rely know(unless i buy the company..) if they sell my
emails or give them to surveillance agency’s
so the best option is to run your own email server
the only reason why i haven’t done this yet(and i hope too soon) is i
haven’t found the time yet.
if you don’t know how to set up a mail server there was recently a post on
this forum about it(and you can always ask on this fourm):
https://trisquel.info/en/forum/how-create-mail-server
and also its a good idea privacy wise to encrypt your emails:
this page has some info on encrypting emails:
https://emailselfdefense.fsf.org/en/