I experienced this exact same issue, just needed to move(drag) xcode to laptop monitor.. external monitor causes crash

The fix for me was, i had my file name on my macbook w special characters "...V2.0...". The image would show in view controllers but not for launch screen. I had renamed the file(after seeing some online recommendations) in xcode.. However, renaming it in xcode doesnt change the true file name in the computer folder structures. After clicking "Show in Finder" i noticed the name w special characters. Updated that and it worked for me on phone and simulator.