With the proxy project, both the creation of user objects and the calls to the API were automated. These functionalities were lost when removing it so you have to do everything manually! One point against! Also many providers will not change their APIs because of a change in PB. Do you not have the possibility of incorporating it and that it has TLS 1.2 support?

The functionality described in the link only works for asmx services but not for svc services. Any suggestion?

Yes, HTTPClient is not as easy to use but much more flexible. It can pretty much do anything rather than just limited to calling SOAP. As long as the .SVC is callable over HTTP then you should be able to use the HTTPClient. But I'm sorry we don't have tech article specific to .SVC. Another option to keep in mind is you can embed a third-party SOAP client COM object if you want specialized SOAP client.