@BurakAtaman

Yes—do it with attachment categories and permissions, not a UI hack. Open the case type in App Studio → Settings → Attachments. Define the categories you actually allow to exist, but for each category set the “Create/Add” condition to a when rule that always returns false (or require a privilege your end-user roles don’t have). Keep “View/Download” allowed so the list still renders. Remove any generic “Links” category so “Add link” never appears. If your org manages security by roles, also remove the attachment create privilege from the end-user access role so the DX API denies creates. After this, Constellation hides the Add files/Add links buttons and shows only existing attachments. If the buttons still appear due to a cached view, save a read-only variant of the Attachments utility in the portal view and reference that variant.