when I select all in my inbox, I mean all not just focused emails. I expect to see all of my emails at once.

Hi there,
Thank you for using Outlook and letting us know about your current experience. We really appreciate your support.
We are so sorry this is happening to you. Our helpful colleagues over the in-app support are more than happy to have this answered. Please contact us through the Help Section of the app (in the Settings) so that we can assist you in the best possible way.
We look forward to fixing this for you.
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.