Using older versions of Outlook for Mac for personal email and calendar
Dear troyjack,
Good day. After thorough research, testing from my end and consulting, it’s been concluded that it is not feasible to remove disable Automatic Reply Banner Notification from the sender side, this banner in the new outlook for Mac it is link to the recipient email address, to notify the sender that the recipient is not available at this time.
As workaround if you don't want to see it you should switch back to the legacy outlook. Reference: The new Outlook for Mac - Microsoft Support
We apologize if we are not able to meet your requirements; however, thank you for bringing this to our attention, we will surely raise you concerns to our Product Team and hopefully this can be included in the future updates. In the meantime, please feel free to post this in our Feedback community by visiting Outlook · Community (microsoft.com) as it is a community monitored by our Product team to help improve user experience with Outlook, via feedback given by our valuable customers. For other concerns, please do not hesitate to add you post in the Microsoft Community Team. Thank you for choosing Microsoft as your partner in business. Your patience and understanding are valued, and we sincerely thank you for your time and cooperation.
Sincerely,
Eben | Microsoft Community Moderator