I am testing the Xcode 27 Beta and new Device Hub app on my MacBook Pro (M5) with macOS Tahoe 26.5.1, but every time I try to create a new Simulator, the process begins to run, but then fails after this message appears that says “Family quit unexpectedly." I looked over the details of the issue, and it is indeed directly linked to the failing simulator creation. Since this issue makes it impossible to Build and Run any app in the new Xcode 27 beta, it makes it almost completely useless for me. I have already downloaded the iOS 27 simulator, but it fails to boot in the Device Hub.
This is due to a known issue in Beta 1 where CoreDevice is not using the newly installed CoreSimulator content, leading to no simulators showing up. The best workaround is to run kill -9 CoreDeviceService in Terminal to get CoreDeviceService to restart and pick up the new simulator content (you shouldn't need to reboot your Mac).