Unfortunately - there is only a regedit change: But I hope that MS listens and gives us an option to choose within Outlook and revert it back easily for everyone.
1) Open Regedit: In the search box on the taskbar, type regedit, then select Registry Editor (Desktop app) from the results.
2) Navigate to Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\ExperimentEcs\Overrides\
OR HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Common\ExperimentEcs\outlook\Overrides\ Microsoft.Office.Outlook.Hub.HubBar
3) If this string "Microsoft.Office.Outlook.Hub.HubBar" does not exist, create it by right clicking on Overrides in the left pane and selecting New->String Value
4) Paste "Microsoft.Office.Outlook.Hub.HubBar" in the new entry that appears in the right pane
5) Double-click the new name
6) Enter "False" in the Value data field.
7) Click OK
😎Close and restart Outlook
Originally posted by LD Fix on page 39 on this MS Forum in July https://answers.microsoft.com/en-us/outlook_com/forum/all/how-do-i-move-email-calendar-people-icons-back-to/6dd0ded4-7a9e-4d0a-aa6f-1870e0ef8ac1?page=39