Parent/Guardian sync for Schools

Hi guys,

On Microsoft Docs I have found this : "SDS will sync Guardians through our CSV method, and create them as Related Contacts in Office 365"

My question is : Is there any way to enable parent/guardian setting (weekly guardian email digest, sharing OneNote class books) without using School Data Sync and SIS? In other words is there a way to add related contact in Office 365 Substrate without using CSV sync to make this work?