How to add the 'All Accounts Inbox' in Outlook for Windows 11

This has bothered me for a decade now. Ever since Microsoft purchased Accompli and branded it Outlook for iOS and Android. It truly is absurd to have this feature everywhere except for their flagship OS... I don't think Microsoft uses this forum to drive product development. Here's a link to the User Voice page to vote on this issue.

Win 11 needs a unified inbox · Community (microsoft.com)

I think everyone is as mad as hell about this. I grew up with Outlook Express and it evolved into a pretty good email program, (with a consolidated inbox irrespective of the IMAP/POP3 account setting - that's nothing to do with it). Outlook Express was then replaced with Windows Live Mail which wasn't as good as OE, but it did have a consolidated Inbox! Forget the various bits of useless rubbish that were the OS mailers, then we get the utter dog's breakfast which is Outlook(New)... I've just spent half a day looking for the non-existent consolidated inbox.

For goodness sake - it's not rocket science! That's a basic requirement for a mail program! I assume that Microsoft think that no-one would want more than one email address (and that would have to be a Microsoft one)...🙄

The whole concept, (Focused - **** is focused??), is amateurish, illogical and unhelpful. None of it comes anywhere near as easy and practical to use as Outlook Express which was released in 1996.

The thing that aggravates me the most is that "New Outlook" is supposed to be unified across all platforms. They promised the same experience everywhere. That just isn't the case.

New Outlook for Mac does have a unified inbox, and it also has the ability to hide past events in the My Day view. Which is the Calendar / Task panel on the right side in the Windows version. In the Windows version, you cannot hide past events in that view. So, when I have a day full of meetings, I must scroll to see what's next, or just look at the meetings I already had.

Outlook for iOS and Outlook for Android also have unified inboxes. It is only Windows that doesn't... That's not even mentioning the Outlook Enterprise Progressive Web App (PWA) is very different than the Outlook.com Web App (OWA). Different functions, different settings. There is no uniformity in Outlook. They must have 6 different siloed development teams working on each of these.

"There is no uniformity in Outlook." - exactly - that's what I'm finding all the time.
If you search for a problem, such as the missing combined inbox, the replies you get mention settings pages that don't even exist in "the most recent" copy of Outlook(New) I installed , er, recently... It's beyond belief that Microsoft would issue a program which looks in the early stages of development like this. I wonder what they'll call the next version - Outlook(New) doesn't really scale, does it? I suggest Outlook(New)(New) and so on. Anyone tried the OEClassic mail program?

All this is exactly correct. Having and older Mac I thought moving to Outlook would improve my unified experience. From the 1st of this month I got a new MacBook Air, went beck fully into the Apple Ecosystem, and have not been happy. Contacts works, unified mail box in Mail, drag and drop, One Drive works, everything just works better and faster. Repaired all the contacts outlook destroyed by adding Notes and Outlook links without any clear benefit. I feel productive again for the first time in 3 years.