Thanks a lot for the help and taking the Fotos. The Goat Link and the Wolf Tooth DM look very similar to me.
I would not be surprised if both of them work? But maybe the save bet is to get the Ultegra one (Wolf ToothDM) since it explicitly lists Ultegra? They are not that expensive, maybe i get one more and give it to a frend for his Gravel bike. Is the GRX Group not able to fit a 11-40T cassette without a Link? I would have thought that. Just out of curiosity whats the max you normally can do on a GRX?
Thanks a lot and i let you guys know how it goes.
BR