Using classic Outlook for Windows in business environments
When you add the account from Outlook it should do auto account setup and pick the right account type. If you choose Advanced pick Outlook.com as the account type to add.
If none of that is working it might be best to create a new Outlook profile, Create an Outlook profile - Microsoft Support.
Just to double check, if you go to File, Office Account, under About Outlook what is the Version/Build?