Outlook Version 2302 (Build 16130.20218) on Windows 10.
I want to set follow ups with a specific date/time on emails. When I select an email and select "Follow Up" I see:

THis simply flags the message. I have looked around and it seems there is a more controlled Follow up where you can set date/time reminders. Here is a great example:

Does this need to be enabled or something?