Clip to Devonthink creating webloc file instead of selected format

i’m not sure what you mean with clutter-free, but as i understand your question, the answer to it is:
Yes, the resulting .webloc-files in Devonthink look more or less like the original webpages in Safari.

No, i clip from 100s different websites.
e.g., as i wrote above, from THIS, OUR actual webpage:

and

From both, as from all other webpages, instead of my chosen format “PDF (Paginiert)”
i always receive a file named “name of the webpage.webloc”!

Sorry, i expected the above URLs to be shown, not the pictures you see now!

The following is an example-screenshot of a file i received in Devonthink, named:
DEVONtechnologies | Wie Sie die Browser-Erweiterungen installieren.webloc
which SHOULD have been:
DEVONtechnologies | Wie Sie die Browser-Erweiterungen installieren.PDF

Just clipped this successfully. A screenshot of the Sorter’s clipping tab would be useful. In addition, how exactly do you clip? Via sharing, via the browser extension or by activating the Sorter?

i clip by, what is the most logical way for me, clicking on the “Clip to Devonthink-symbol” in the Safari-toolbar (i think this is the "browser extension)
and then choosing “Format: PDF (paginiert)” in the popping up window, then choosing “Hinzufügen”.

Sorry, i don’t know what the “sorter’s clipping tab” is.
Is it this?

Exactly this popping up window where you choose e.g. the format and enter additional details like comments.

This produces a .webloc, not a .pdf!

No problem at all over here using the same settings. Do you use any third-party tools to block/filter network traffic, e.g. LittleSnitch or anti-virus protection?