This is why there is no official way to access iMessage on non-Apple devices, such as Android smartphones and Windows computers. Although there are tools to send SMS from PC, iMessage is not one ...
If you performed an upgrade the first time, activated Windows 10, and then clean installed Windows 11 on the same PC, there will be no activation issues, as the OS will pull activation details ...
Look for VPNs that offer native apps for Windows, which simplify the setup process. A VPN like X-VPN is compatible with both Windows 10 and Windows 11, and it's easy to install and use on your PC.