Sorry for the delay in responding this. In order to use ApolloX on Windows, VSCode has to be connected on WSL2, as you can see from the images here: GitHub - toradex/torizon-experimental-torizon-ide-v2-docs: VS Code Torizon Integrated Development Environment Documentation (note the bottom left of the images indicating WSL being connected). Otherwise you will receive the message about the extension not being available.
You can check the Microsoft documentation on how to use VSCode with WSL2: Get started using VS Code with WSL | Microsoft Learn.
Hope this helps you.
Best regards,
Lucas Akira