I think it will be around dashboards and custom events for the most important metrics after configuring the extensions for ABAP and HANA DB, also you can use the synthetic monitoring for ABAP systems.
Regarding SAP Java-based systems such as SAP Business Objects, and Cloud connector. should be possible to install OneAgent normally for full stack monitoring.
as for SAP Fiori, you can use agentless monitoring and Synthetic monitoring.
Regarding SAP SaaS-based solutions such as Ariba & Success factor, you can use the following methods only
- Synthetic checks for availability
- Real User Monitoring using the Chrome Browser Plugin