Even cannot download from here, too
Same issue here. For context, I was using the Xcode 15 beta since June and everything worked just fine. However, after Xcode updated through the App Store last night, none of my simulators will download. I get the same "Failed with HTTP status 400: bad request" error.
Removed and re-downloaded Xcode, issue persists. I can't figure out what's going on here.