Some may exist overseas. I have bought NLA parts from Poland with no problems, even uber rare pre-merger AMG parts.

Found this: https://2407.pl/en/mercedes-brand/traction-000-070-69-75-18765000/

and

https://welldoneparts.com/en/about-us/

If you go overseas, I suggest always asking first if they really have it in stock. Of course, it is a trade off with price vs. time and effort making one.

Those plastic ends -- could you 3-D print them. I ask since I had the W116 rear heated seat pods (go on the B pillar) and the black bezel 3-D printed when 3-D printing was just starting to go commercial. I got some quotes for some parts recently, and pricing is shockingly low. Getting the CAD drawings is the first step, which means having one in hand. The rod appears to be listed as 200mm. If you had one of the plastic ends, you may be surpricsed at the price for new 3-D printed ends.