ActivityMonitor & SystemStats are not recognized as valid Permission Ids

There is a comment at the top of the manifest that indicates you should not be making manual edits. This error could have been avoided by using the manifest editor in VSCode. You just have to click the manifest from the file viewer.

Thanks a lot. I appreciate your support.

Those aren't permissions. ActivityMonitor is a module and SystemStats is a class in the System module. You don't need permission to access either of those things.

You can see the list of permissions and associated modules here:

https://developer.garmin.com/connect-iq/core-topics/manifest-and-permissions/ 

In general, if your code references a module that requires permission, you will get a runtime error if you haven't specified that permission in the manifest.