Which one is the best between Xcode 14.3 and Xcode 15 Beta. As I have the two on my laptop and my laptop is out of storage, which make it run slowly, I don't know which one to uninstall and the one to spare. Your advice will be really appreciated.
Xcode Features
There's no definitive answer to your question. Typically, once you've verified that your project can build and run under a newer Xcode version with any issues, then the newer version may be all that your need.
One thing to keep in mind is that you can't submit your app to the App Store via a beta version of Xcode (or submit a macOS app for notarization, if you're not distributing via the App Store). If you think you will need to do that, and you don't have another Mac with Xcode 14.3 that you can do the submission from, then you should probably keep 14.3 on your laptop.