Copay is written in Electron which means that it is entirely cross platform by design, Windows Store is just a cute wrapping in this case. You can git clone it and use it with node and npm but this is boring work and nodejs tend to throw errors at you because the compilation process of Copay is designed more for a Linux kind of system with things like rms etc in package.json.

1. Use Fiddler, Wireshark (on VirtualBox) or https://store.rg-adguard.net/ (Directly) to generate links to *.appx file.
2. Open the downloaded file as an archive (with WinRaR for instance).
3. Create a new directory in the location you find most entertaining.
4. Extract .appx file contents into that directory.
5. Create shortcut to <your path>\Copay\app\Copay.exe and run the app.

Tested for Copay v7.0.3.

Download the pre-compiled windows versions from the releases tab on the github page.

https://github.com/bitpay/copay/releases