I get a different error UpdateTimedOutError: Updating took more than 5 seconds on beta 16.3 Xcode , no matter how many times I refresh the preview. I will file a report with logs attached.

Do you mean this? @MainActor public func layoutUI() -> some View { Group { provider.createView(completion) } } This has same error, and I cannot put ViewProvider in a Group because ViewProvider is not conforming to View, it is a plain struct.