The required privileges are detailed here : https://learn.microsoft.com/en-us/purview/audit-search?tabs=microsoft-purview-portal

"To access audit cmdlets, you must be assigned the Audit Logs or View-Only Audit Logs roles in the Exchange admin center. You can also create custom role groups with the ability to search the audit log by adding the View-Only Audit Logs or Audit Logs roles to a custom role group."