Hi Gaurav295,
To answer the first question, for the third-party issue, I would recommend you to ask the third party for more effective support.
The second question, based on my research, we can install the DirectAccess feature on the bulk servers with System Center, to configue this feature automatically, I recommend you can start the powershell script to achieve this, then you can deploy the
powershell script on bulk servers with system center.
To configure DirectAccess, please refer to this article:
DirectAccess in PowerShell
I hope this helps.