Tldr: create a new visionOS app from the menu, it'll prompt to download the support files correctly. Had a similar issue after doing the Xcode 15 beta 2 downlo

Tldr: create a new visionOS app from the menu, it'll prompt to download the support files correctly. Had a similar issue after doing the Xcode 15 beta 2 download with both iOS 17 and visionOS 1 simulator checked. When creating a new visionOS App it would tell me that I'm missing the device/simulator support and prompted to install it. After confirming this it would show a download for a build that ended in xxxxxxxg instead of xxxxxxxf as was part of the download, so I assume that part was updated in the background and now is no longer the correct reference. HTH