Hi @Rossy - ,
Do you mean you would like to sort by "To" then "Date Sent" in Outlook for Mac? If this is the case, I am afraid there's no such an equivalent feature or alternative available in Outlook for Mac at present.
Currently, as mentioned in this document, we can only select one option to sort items by via Organization > Arrange By:
Given this, personally I'd recommend just sorting by "To" in Outlook for Mac.
I noted that a similar feature request has already been posted into the dedicated feedback portal for Outlook and I've voted for it. I'll leave the link below in case you or others see this thread would like to add vote or comment there as well. Hopefully this option can be added to Outlook for Mac in the future.
Sent Items SubFolders or any subfolder Sorting Option (Sort by Sent To and then Date)
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