Copilot was hallucinating. Unlike other Office apps, there is no "Application.Run" method in Outlook.
As far as I know, Outlook Security has pretty much blocked the ability to run a Macro from outside of Outlook. One method I've used in the past, was to add the Macro to the Quick Access Toolbar and then use a scripting tool like AutoIt to "Send" keystrokes to a running, visible, Outlook session to execute the Macro. e.g. "{Alt Down} {Alt Up} 1" will execute the first item on the QAT.
You might be better off using something other than an Outlook macro. Any office app that lets you use CreateObject("Outlook.Application") (e.g. Excel) can then do pretty much the same thing your Macro did, using almost identical VBA code. There are lots of other options. Scripting languages that support Outlook Automation (e.g. AutoIt) and C# using the Outlook Interop libraries.