Thank you for posting your concern here.
If I understood correctly your intended scenario...
You need to be able to access your resources using only a VPN solution(without using the RDP tool) but I wonder if you are looking to set up this VPN on your WS Server by provisioning a L2TP/IPSec VPN(just to mention to you an example) or as well as to complete this task with a stateful Firewall solution for P2P/P2S VPN.
Have you thought of using force or split tunneling for this scenario?
Looking forward to hear back from you.
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