My colleague has a hub site with a series of related SharePoint sites. On one site he has added a highlighted content web part to show policy documents stored in a document from one of the other sites. But it is showing duplicates of each file for some reason.
Sorry, if it's not a helpful answer, but there is no setting in the Highlighted content webpart to trim duplications. Also, KQL syntax does not support adding something like
trimduplicates=true to the query.
You can try experimenting with the filters instead of KQL to see if you can get rid of duplicates this way.