My device is running iOS 12.2, but the latest Xcode version available (on the store, and directly from developer.apple, which just pushes me to the store) does not provide the support files for that iOS version, so I cannot build to devices.
Here's the error message from Xcode:
And my Xcode build running on macOS Mojava v.10.14:
Are there any reputable other places to download a more recent Xcode beta from (or just the support files, in Xcode > Contents > Developer > Platforms > iPhoneOS.platform > DeviceSupport), or am I missing something here?