Dear @Bryan,
Thank you so much for contacting Microsoft Q&A Support.
Based on your description, I would like to ask that do you see a confirmation message when deleting emails from your Inbox, or only when deleting them from the Deleted Items folder? In my test setup, I don’t get any confirmation when deleting from the Inbox. But when I delete something from Deleted Items, I do see a banner that says: “Do you want to permanently delete the selected conversations?”
Also, I checked Microsoft’s documentation and couldn’t find any official way to turn off that banner in the Mac version of Outlook. It might just be a limitation of the Mac client.
Here’s a situation that seems pretty similar to what you’re experiencing with Outlook on Mac: How to disable prompt for confirmation before deleting email in - Microsoft Community
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