register your own domain name, either for personal or professional purposes
take some basic security precautions on your domain registrar account, use a long complex password that's not used for any other service anywhere else on the internet, and set up some form of 2FA for logins as well.
control your own authoritative DNS zonefile and choose where to set your MX records
choose a 3rd party email service such as the other recommendation here, fastmail, and set the MX records, SPF and DKIM appropriately