S/4 HANA cloud, SAP Analaytics Cloud (SAC) , B/4 HANA

I work as ML Engineer. I use python , Other cloud services. I moved to a company, that is a SAP shop. They want me to get SAP certified. I see there are various products. It's kinda confusing where to start with. Should I start with SAC or S/4 Hana cloud or B/4 hana. Any suggestions. I'm completely new to SAP space . Any suggestions would be highly appreciated.