@Anonymous Only built-in connectors support to access resources on Private IPs on the VNET integration feature as they run alongside of the Logic App standard host runtime. Whereas Azure connectors (SAP in your case) run in a shared environment and they don’t support to access resources on Private IP addresses and resources must be accessible from the Internet or via OPDG if it’s in a private network.
Unfortunately, as we don’t have SAP as a built-in connector yet so you need to use OPDG to connect to SAP from your Logic App Standard environment. Connect to SAP systems from Azure Logic Apps document is still valid for the logic app standard environment. The product team is working on the feasibility but there is no ETA to be shared as of now. Once this feature will be in the preview we will update our document with more details.
We can still enable VNET integration while workflows have Azure connectors but are required to open traffic to Azure connector Ips on NSG or NVA/F/W on VNET integrated subnet along with target system on public IP.