The constructor is internal so you can't create it yourself. The

application()

is the only way to get one. What's your use case?

We wanna theme Label, where-by it'll be themed before being added to the App

Are you using the ThemeManager? Setting a theme will ensure any View added to the app, even if the all has already been running, will be themed (if the theme has the right behavior for the view).

As a module??

No need for an additional module. It is available for injection just like Display. Simply do:

application() {
    YourApp(
        //…
        textMetrics = instance(),
        // …
    )
}