I have 2 subaccounts:
On subaccount A inside the Portal service, there is a 'sap_hcmcloud_core_odata' destination created by the integration of SF with BTP. This destination is used for the Portal site template to load the SuccessFactors header and footer.
Also on subaccount A on the subaccount level, I created a 'sf_odata' destination using Neo CLI hcmcloud-create-connection command. I wish to keep the possibility of accessing the application without the Portal site template, so that's why I'm keeping sf_odata and not replace it with 'sap_hcmcloud_core_odata' in neo-app.json (which I assume would be possible). Both destinations are of type OAuth2SAMLBearerAssertion.
Because the corporate SSO is set as the default idp for subaccount A, it's being used for all services.
For continuous developments of 'myExtension' on subaccount B: