If it is under 100 mails per day just use gmail. If you are scared of abuse usw postfix+opendmarc (for sending), but IP/domain reputation takes time. Otherwis

If it is under 100 mails per day just use gmail. If you are scared of abuse usw postfix+opendmarc (for sending), but IP/domain reputation takes time. Otherwise one provider that offers sending+mailbox or two providers for the use-cases.