Hi @Rising Flight ,
Thank you for posting in this community.
SharePoint Online permissions are separate from Exchange Online. To grant SharePoint reader access, you don’t need to rely on Exchange Online roles. Instead, grant read permission directly in SharePoint Online.
Reference:https://support.microsoft.com/en-us/office/share-a-site-958771a8-d041-4eb8-b51c-afea2eae3658
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