Merge Mutiple Document Libraries into One Document Library with SharePoint Online

Arun_J_YadavYes, using SPFx you can easily achieve if you want to show them as reference/links with their metadata. It will be difficult to get the complete doc library look and feel if you are fine with them appearing in some sort of tabular structure it's complete doable.

As you want to avoid duplication I can suggest another approach Highlighted content webparts where contents from different places can be brought together. If you want to start this would help. https://sharepointmaven.com/how-to-roll-up-content-from-sharepoint-sites-using-highlighted-content-web-part/

Thanks,
Vik
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