SOme useful information here https://learn.microsoft.com/en-us/azure/purview/concept-best-practices-network#option-1-use-public-endpoints
IN the creation process you can configure both private end points and public endpoints. ONce created you are given (properties label)
Atlas endpoint like https://purviewaccount242581.purview.azure.com/catalog
Scan endpoint like https://purviewaccount242581.purview.azure.com/scan
All ranges used by Microsoft are here https://www.microsoft.com/en-us/download/details.aspx?id=56519 but you will not find any purview specific, just add them all...