Show my most recently sent message on top in Mac Mail
As far as I'm aware, the closest you'll get to this is to ensure you expand all conversations. However, there are preferences that may impact on the expansion.

So, let's try the following:


In Mail, go to Mail > Preferences
Click on the Viewing tab
Ensure the Include related messages checkbox is ticked
Ensure the Show most recent messages at the top checkbox is ticked
Exit Preferences
Now within Mail go to your Inbox
Ensure the filter at top left is sorted by date and that Newest Message on Top is ticked
Go to the View menu and ensure that Organise by Conversation is ticked
Go to the View menu and select Expand All Conversations (Note: This won't place a tick there, it just expands them)


After doing the above you should get something close to what you want.