None of the examples in the article exhibit the 'via' UX. They were all sent with an aligned RFC5321.MailFrom and RFC5322.From (i.e. domain name used in both of those values is the same), those not matching is the most common reason to have the 'via' displayed [0]. They do have display names which pretend to be SendGrid.

0: https://support.google.com/mail/answer/1311182#zippy=%2Ci-ca...