Using classic Outlook for Windows in business environments
Hello,
Yes, the new Outlook should support POP3, support for 3rd party accounts. Reference: https://support.microsoft.com/office/656bb8d9-5a60-49b2-a98b-ba7822bc7627
About purchasing only the Outlook 2021, you can purchase Microsoft Outlook 2021 as a standalone application for Windows without the other components of Office 2021.
Microsoft Store: Microsoft Outlook (PC or Mac): This standalone version is compatible with Windows 11, Windows 10, and macOS. Price: $159.99. You can find more information and download options on the Microsoft Store page: https://www.microsoft.com/en-us/microsoft-365/p/outlook/CFQ7TTC0HLKQ?activetab=pivot:overviewtab
Kind Regards, Myk