Hi there;
Depending on scale and preference, you have three options available;
a) Build a custom integration using the Dynamics CRM SDK and SAP SDKs.
You could build a console app, Web API service or Azure function that talks to CRM and SAP. This pushes the processing out of SAP and CRM distinctly, and removes the burden of having to pay-per-action as you may need to do with Logic Apps or similar.
b) Build a Logic Apps driven function.
You may need to bridge the gap between SAP and the outside world (i.e. stand up a custom web service that Logic Apps could talk to), but for specific integration tasks with limited dependencies and volumes this is the solution I would lean towards.
c) 3rd party products.
Your options appear limited here - MuleSoft may have a connector to both D365CE and SAP. 10 years ago I would have recommended Scribe, but I wouldn't go down that pathway now.
Hope this helps you choose your pathway forward!
-Bruce.
