I had the same problem today. Xcode was stuck at “Preparing to download” for components, and xcodebuild -downloadPlatform iOS was stuck at the same stage. I was using my phone’s hotspot. After switching to another Wi-Fi network, the download started working normally. So at least in my case, it was a network/CDN issue rather than an Xcode installation problem. If you’re seeing this, try another network before reinstalling Xcode.