Hi Aaron,
Thanks for sharing. Can you confirm your Outlook version? It seems like older versions of Outlook default to matching destination formatting instead of keeping source formatting on MacOS; however, this was resolved in an Outlook update: Paste on Mac - no highlights - #7 by Gaurang_Tandon
If you are already up to date with version 16.97.2 and still have the issue, please let me know.
Best regards,
Alexander