I don't know if it even matters. Emails are like postcards, easily read by anyone who handles them. Just because your mailbox provider isn't google, doesn't me

I don't know if it even matters. Emails are like postcards, easily read by anyone who handles them. Just because your mailbox provider isn't google, doesn't mean it doesn't come in contact with google somewhere else. If you really don't want them to be able to collect the content of your mails then you and all who write to you have to encrypt them. And then you would still have the problem of the metadata to be accessible.