Deep nesting suggests that you need to break parts out into their own views (or pull logic out into their own functions). Like the close box in that file, it’s a great candidate for turning into its own view, or at least moving it’s action into a separate function.
This! It’s generally a good idea to have a lot of smaller “dumb” views that are stateless and depend on their parameters, and a few “intelligent” views that bring the children together and provide state logic. That puts reasonable boundaries between the view and business logic, even in declarative code like SwiftUI.
I’m not a Swift or SwiftUI expert, but have written declarative UI quite a bit. Don’t imagine some base best practices would differ too much.