Dear @Eric Zhang,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, you wonder if the Quick Links web part forces PDFs to open in the SharePoint viewer by design, with no configuration to change this behavior.
This behavior is expected and by design in SharePoint Online.
When a PDF file is added to the Quick Links web part, SharePoint always opens the file in the built‑in PDF viewer and shows the “Back to document library” option. Even if you paste the direct file URL or add query string parameters, Quick Links still treats the target as a document and enforces the default viewer experience.
At the moment, there is no supported setting or configuration in the Quick Links web part to change how PDFs open or to suppress the “back to library” behavior.
Here are some workarounds you can try:
By selecting Open link in new tab, the PDF opens separately without disrupting the current page. This can reduce the need to use the “Back to document library” navigation and provides a smoother user experience.
To help improve this experience, we strongly encourage you to submit feedback directly to Microsoft so it can be reviewed by the SharePoint product team. I encourage you to submit feedback through the Microsoft Ideas Community at Ideas · Community so that the product team can review user preferences.
Our product team is in charge of the site, and they constantly check customer reviews and feedback, The higher votes, the more attention the related team will pay on. And a lot of the features are developed and improved based on customer feedback.
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