My advice for anyone else coming across this: Ignore the Apple validator and check if it is working on a device. In my case, I also had the "cannot fetch app site association" on the Apple validation tool, but it worked anyway on my device (the link redirected to the app). If it's not working, there are a lot of possible reasons in this SO post - https://stackoverflow.com/questions/32751225/ios-universal-links-are-not-opening-in-app. The branch.io validator was also helpful for me.

The other interesting line is: closure #1 in KitRendererCommon(_:) + 168 (UIKitApp.swift:37) Xcode shows me this line as the culprit of the crash. Is there a bug with the mix of UIKit and SwiftUI code?

@AlanXp If you don't have access to another Macbook with non-beta Xcode installed, like me, then I guess you only have two options: Boot MacOS from an external SSD, with Xcode installed, like @fbronner suggested. Use Xcode Cloud. I found Xcode Cloud to be a simpler solution in my case. I was able to set it up rather quickly. I wanted to start using it for some time and this was a good moment to do it. The free trier is largely sufficient for me. Still, I really think they should make this limitation more explicit when updating to beta. PS: If you are having issue with Xcode 16 beta, note that you can still run Xcode 15 from the terminal usingopen /Applications/Xcode.app/Contents/MacOS/Xcode. This won't allow you to archive the app for release (you get an error later in the process), but it may be useful for testing.

Still having this issue with iOS 17 and iOS 18 on a real device (works with the simulator). Any solution?

Still having this issue with iOS 17 and iOS 18 on a real device (works with the simulator). Any solution?