I have 2 x Office 365 business email addresses and have used EMClient, as I would Outlook, to access the second address as a delegate of the first.
Several years ago, when I still paid for VIP support, I raised bug as when I emptied Trash, the Trash folder for the delegated account was never emptied.
I had somebody connect to my PC and I submitted much evidence.
The problem was identified as a bug.
But, today, several years later, the problem has not been fixed.