I have exactly the same issue, currently running Sonoma 14.4.1, Xcode 15.3 and simulator iOS 17.4. Dragging and dropping from finder folder to files folder in simulator doesn't work as it used to. When i drag wav or mp3 audio file, simulator opens messages app. Also I observed that when i copy audio file from mac finder (by clicking on a file and selecting copy) and paste it into files in simulator it creates txt file with name from the audio file. It's either a bug or Apple decided to remove this feature from simulator which would be really a pity for us - audio developers :[