Apple Mail - Disable Unified Mailbox

A user cannot remove the Inbox.

However a user can create new Mailboxes and apply Rules to manage incoming mail.

Create new mailboxes

https://support.apple.com/guide/mail/create-or-delete-mailboxes-mlhlp1021/mac

Use Rules to manage your messages

https://support.apple.com/guide/mail/use-rules-to-manage-your-inbox-mlhlp1017/ma c

Exactly the same problem - wanted to go all in with Apple but as I manage 10 email accounts, Outlook is the only practical solution. I picked this up direct with Apple and it's a no go. They seem to think we are asking for the moon when all we want to do is change the view! Frustratingly, the mail app on iPhone and iPad is perfect - yes, all the inboxes are together but then everything else is arrange by account...

According to the forums this debate has been running for years so my only advice is to stick with Outlook... Sorry.

As to mailbox organization, there is no difference between iOS and macOS.

All inboxes are unified and can be viewed individually. Same for the standard mailboxes.

All other mailboxes are separated under there own accounts.

They are assembled by account in the Unified Inbox folder:

But, personally, I won't be able to use Apple Mail if I can not display by email by account.

Then you'll have to find another email client.