How to provide the WhoId access to Opportunity and Platform Opportunity (Custom Object) to sync the tasks, Activities between the objects?

Requirement:

I want to sync the activities, Tasks, and events between the opportunity and Platform Opportunity(Custom object) without creating a duplicate record in the Tasks, Activities, and Events, and syncing of the records should work Vice Versa too. #Sales Cloud #Salesforce Developer #Salesforcearchitects #Senior Salesforce Business Analyst