현재 xcode 13.3에 ios version 15.4에서 unable to boot simulator 문제가 있다.
https://developer.apple.com/forums/thread/702608 여기에 issue가 등록되어있는데, 지금으로서는 ios version 15.2를 사용해야지만 문제가 안생긴다.
Just open xcode -> windows -> devices and simulators, click on the Simulators tab
click New, click on the OS Version dropdown and choose "Download more simulator runtimes",
download 15.2 and create a new simulator with 15.2 as OS Version.