This has not changed, to my knowledge, over a very great many versions of Outlook. I think it's been this way since Office 2007.
ALT+V, AB,D [View Tab/Ribbon, Arrange By option, Date (conversations)]
If that alone doesn't do it, then you need to make sure that both the Show in Groups option is on (and it's a toggle) if you want the groups to show (e.g., Today, Yesterday, etc., before the conversations themselves):
and/or Group by Conversations is on (and that's the default state). ALT+V,AB,V (the V is View Settings, which will bring up that dialog) then, in the dialog navigate to the Group by button and make sure it's set for Conversation (ascending), and then navigate to the Sort by button, and set that to Date, with the descending option checked if you want conversations with the newest messages to appear at the top of your inbox, or ascending if you want oldest conversations first with newest at the bottom of the inbox.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
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