Scrap the split inbox. Unnecessary. Assuming its just an opportunity for ad income given the "other" folder is always topped with an ad!
Thank you for using Outlook Mobile and sharing your ideas with us. We really appreciate your support.
It is currently already possible to turn on/off the Focused Inbox, to do so go to settings then tap the toggle switch to turn on/off the Focused Inbox option.
Having trouble finding the feature? Let us know through the Help section of the app. You may reach them by going to the app’s Setting > Help and Feedback > Contact Support.
Thank you again for your support, we look forward to hearing more of your ideas very soon.
All the best,
The Outlook Mobile Team
PS: Please use the Help Section of the app for any questions, we are not able to see replies to this address.