Problem: The data merge does not function if you reference assets using an absolute path, meaning the assets are not located parallel to the data source file in macOS
Adobe provided a temporal solution for the issue:https://helpx.adobe.com/de/indesign/kb/data-merge-not-working-absolute-paths-macos.html
1. Close InDesign.
2. On macOS, navigate to <installation directory>\Resources\Cookies\ENABLE_POSIX_PATH.
3. Delete ENABLE_POSIX_PATH or rename it.
4. Start InDesign."