Since the Windows Calendar app is no longer available, I just wrote a piece of code, especially because I often need to know the week numbers in my daily business.

The two scripts run the same PowerShell code under the hood. Unlike Batch, the JScript sibling executes it without any flashing CLI window if the *.js extension is associated with wscript.exe.
By default, the light or dark theme is applied automatically based on the corresponding Windows settings.