I've been using Xcode since it was Project Builder. It has improved in many ways. And since the advent of the App Store, the insufferable/inexcusable nightmare of "signing" has vastly improved.
Most of the problems I encounter now resulted from the fiasco that is SwiftUI. I used to really enjoy development, and built a few mobile apps singlehandedly... even at a well-known company or two. But now I'm struggling to get one chunk of functionality at a time done on a from-scratch app, because SwiftUI and the underlying "reactive" paradigm were so poorly conceived and defectively implemented. Development is now miserable drudgery, and I never feel confident about the result. The absurd gymnastics to trick the UI into doing what you want; and the hypocritical, conflicting edicts for Swift and SwiftUI... it all barely hangs together.
The fact that Apple rolled out a new UI toolkit that didn't support the most fundamental paradigm in mobile applications, a stack of progressive views for the user to proceed through, tells you how far off the rails they went since introducing the original and solid SDK.
And testing is going to be a nightmare... or simply futile.