Windows environment variables at appsettings.json

Question

I'm trying to set AccessKeys in appsettings.Development.json to point to my OneDrive folder. Since some team members have their OneDrive at different folders, I was trying to use Windows environment variables like this:

"AppSettings": {
    "AccessKeys": "%OneDrive%\\project123\\keys\\",
}

However, the above attempt is not working since the file is not being found.

    internal XDocument ReturnFileContent(string filename)
    {
        string documentPath = _configuration["AppSettings:AccessKeys"];
        string xmlFilePath = Path.Combine(documentPath, filename);

        var aux = File.Exists(xmlFilePath); <- always false

        //...
    }