For users who want a completely clean sidebar without the "Quick Access" entry at all, you need to edit the Windows Registry. Warning: Incorrect registry edits can harm your system. Follow these steps carefully.
If you don't want to fully disable Quick Access but just clean it up:
Open Folder Options (follow Steps 1-3 from Method 1 above).
By following these methods, you can easily disable Quick Access in Windows 10. Whether you prefer to use the File Explorer options, Registry Editor, or Group Policy, you can choose the method that works best for you.
Choose the method that best fits your workflow, and enjoy a less cluttered File Explorer experience.
Close the Registry Editor and restart your computer (or restart File Explorer via Task Manager). The Quick Access entry will no longer appear in the left sidebar.