None of this is surprising. I was a sw engineer at 23andMe about 5y ago. Their backend consisted of some of the worst python/django spaghetti code I’ve ever worked on. There was also no engineering culture whatsoever.
System Preferences was rewritten for Ventura in SwiftUI, which is absolutely not ready for production, especially on Mac. Speaking from personal experience, I recently wrote a simple macOS app using SwiftUI. I found the framework to be slow (why does it use so much cpu/memory when idle??), unintuitive, and awkward to use. Despite being in its 4th year, SwiftUI is still very much beta software, and I wouldn’t recommend using it for anything serious.