malte83 wrote:
Just recently switched to macOS Tahoe on a M1 Air - am I missing something or is the drag and drop function of selected thumbnails to a finder window disabled / not possible anymore? It used to create a new PDF file of the selected pages with the original PDF's name + (dragged).pdf. Why does this not work anymore?
Additionally, when I select a few pages from the thumbnail and right-click on them to "export as..." it exports the whole PDF file and not just the selected pages. That's very unintuitive.
Any (quick) workarounds, are there any settings I need to change?
Your Settings for Preview are limited...

if you have shut down and restarted more than once and compared your results?
>Shut Down
To trouble shoot further you can:
—A SafeBoot Start up your Mac in safe mode - Apple Support will sort many anomalies
Does a quick disk repair before it fully boots up, and certain system caches get cleared and rebuilt, third party system modifications and system accelerations are disabled temporarily.
Login and test. Reboot as normal and test. Caches get rebuilt automatically.
This test will tell you if third party interference; most extensions etc are not loaded in safe boot mode.
—Test issue in another user (or guest user) account Change Users & Groups settings on Mac - Apple Support
This will tell you if it a universal issue or isolated to your user/admin account.
To be proactive you can file a bug report / submit your feedback here:Feedback - macOS - Apple
You can try a true PDFeditor if your issue persist— there are many third party to choose from.
Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus
all known to cause issues on the macOS