Searching for a Blog or a Wiki to connect Fiori KPI (S/4) to an ECC Odata Service

Hi Team, I am trying to use the Fiori KPI of an S/4 system (2022) on premise, but using the data of an ECC system using Hana database. It seems to have a solution to code the Odata service in S/4 and using the ABAP code access the Hana database of ECC. But it is not sexy.