Currently I have several email accounts when rules move unread messages to folders so that the inboxes only contains uncategorised mail.
I have a mixture work and home accounts but am man and poor at multitasking I prefer to deal with them separately and so use then individual inboxes rather than the combined one in favourites.
Two or three of my accounts only receive occasional but relatively important emails It would be helpful to be able to see that there unread emails in the collapsed form . Currently, it appears the only way to know they are there is if in Favourites the All inboxes count is zero but the Unread is still showing a number; and then to locate expand each account individually.
My wife frequently tells me that I can’t multi-task because I’m a man so I use it to my advantage when it suits me - I can’t go into that here save to say that I can do a lot of things with my eyes closed.
I’ve a similar situation, I have a mutitude of accounts through my companies that I can access if I choose, however, there are 9 accounts that I use frequently, 6 for mostly incomming mail.
I have rules to direct incomming mail to individual mailbox/folders or whatever you call them.
I first created and specifically named, in each account a new folder that identified each account, each of these new folders I linked to Favorites. (to link a folder ‘right click’ -> Add to Favorites)
I did this as to simply link the ‘inbox’ of each account I would have ended up with 9 ‘inbox’ folders.
The links show in Favorites when the accounts and Local Folders are collapsed.
I created a system of complex ‘Rules’ to divert to other sub-folders that I have, they don’t need to be they can be in their most basic form, to point to each of these folders.
Now all mail is filtered to individual folders linked to Favorites & Unread to show what is where.
This works for me; maybe it will be of some help to you.