I see comments on TSW2 YouTube videos stating that the DB BR 187 has it's sound copied from the 185, and how that's unauthentic to the real 187. If so, would it ever get changed by devs?
This loco was made by Skyhook studio. They have never patched obvious bugs in their previous DLC Cane Creek (flying rocks / loud traffic sounds for example), and that they have never communicated with players, so you should keep your expectations (very) low. DTG also explained Skyhook doesn't have the right audio sound recordings... They are now worse than Rivet studio and their Arosa Linie DLC with its scenery looking like an old Xbox 360 game, even on a Series X.
There was a mod made for pc to put the right sounds on the train. The below comment was made by skyhook “ ”
Yes, the sound used is from an outdated version of the BR146/185 which has now been improved on these locomotives, and is inaccurate for the BR187 This is how the real one sounds. The video you linked above is a PC-only mod which introduces better sounds. No comment wether or not it will become official or if Skyhook will do anything about it. I'd say to expect no, as even DTG themself are trying to distance themselves from Skyhook's model.