Hi @agc and welcome to the checkmk community.
oh well … SAP and monitoring, this is kinda difficult topic.
First to your monitoring of HANA systems. Do you have a scale-up or scale-out system, which version are you running and have you a multi-tenant environment?
In general you need some preparations to monitor an HANA database, like creating a user with proper roles inside the database and optional store the credentials to hdbuserstore.
For monitoring the ABAP side of an SAP system, the legacy sap R3 check exists but I personally not recommend to use this, because this plugin is using the CCMS and this isn’t supported anymore by SAP since, I guess, 10 years. You also have to configure a lot of stuff to get your metrics inside SAP to be collected and then collected by checkmk.
I would rather recommend to use your SAP Solution Manager and the Monitoring and Alerting Infrastructure with the 3rd party alerting connector to write a log file which is monitored by checkmk via event console.