In my experience, to setup the new SAP Support Hub Connectivity, it is best to just follow the SAP_SUPPORT_HUB_CONFIG Task List from transaction STC01:
However, there are 2 important prerequisites:
- In transaction RZ10 set parameter ssl/client_ciphersuites to 918:PFS:HIGH.
- When creating your anonymous client SSL certificate, include the VeriSign and Symantec certificates from site https://support.sap.com:

This is how it looks in transaction STRUST:

With this your Service Point is created successfully:
The one warning I get is about a not defined Server group, which I can take care of later:
Welcome to the new SAP Support Hub connectivity world
😉