Just so we are both crystal clear, what are you referring to when you say Outlook? Certain things suggest the standalone email client while others suggest Outlook.com. You also say a couple of things that seem like they refer to the Windows 10 Mail App, which is different from either any Outlook client or Outlook.com.
Can you identify what Outlook you're using, including version, e.g., Outlook 2016/2019/365, if it's the client or Outlook.com? Is the Windows 10 Mail App in the mix somewhere?
I have to know where to look, precisely, in order to give you the answers you seek, if I can do so.
Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041
The purpose of education is not to validate ignorance but to overcome it.