I was also struggling to get all the unread emails (including from the subfolders) in Outlook Office 365. The closest I could find was the following search query:
In case of Desktop client, this can be achieved with the Search Folders.
Search Folders -> Right Click -> New Search Folders -> Unread Mail
But, unfortunately this feature is ...
Please follow these steps
Click on your avatar in the upper right corner and choose My account.
After that, you will see your profile.
Click on More actions>>Edit profile>>Edit name and enter the name you want to change to.
It seems that you can simply create a mail filter on Outlook that moves all files in Junk into your main Inbox as a workaround. The steps are as follows:
Click on the gear icon on near the top right corner in Outlook.com
Click on the "options" menu item
Select "Inbox and sweep rule" on the sidebar
Click on the + symbol to add a new rule