How to get "System Settings" of the System User in OrganizationServiceProxy in Azure based WCF RESTful API?

Hi,

I have WCF RESTful API hosted on Azure which use to communicate between MS Dynamics 365 to Web Client. Everything is working correctly but I want to "System Settings". Actually, I need settings of "Use the new Unified Interface only (recommended)" for the login user. Can anybody please suggest me how can I get that?

I have following code to for Authentication using OrganizationServiceProxy.

public RequestData authentication()
{
    ClientCredentials clientCredentials = new ClientCredentials();
    clientCredentials.UserName.UserName = "Username";
    clientCredentials.UserName.Password = "Password";
    Uri oUri = new Uri("Organization Url");
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
    ServicePointManager.ServerCertificateValidationCallback =
    ((sender, certificate, chain, sslPolicyErrors) => true);
    OrganizationServiceProxy _serviceProxy = new OrganizationServiceProxy(oUri, null, clientCredentials, null);
    
    if(_serviceProxy != null)
    {
        OrganizationServiceContext _orgContext = new OrganizationServiceContext(_serviceProxy);
        return true;
    }
    else
    {
        return false;
    }
}

Screenshot "System Settings"

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