Refactor Away from an Anti-Pattern

Background: Native [platform] app, [SwiftUI+Combine / Compose]. I think
this code has slid into an anti-pattern. Here it is:
[paste the offending file(s)—e.g., a massive view model, a god singleton,
callback nesting, or a view stuffed with business logic]

Use case: Confirm what's wrong and walk me out of it incrementally,
without a risky big-bang rewrite.

Implementation details: Identify the specific anti-pattern (massive
view model / god object, singleton overuse, callback hell, logic in the
view, feature envy). Explain the concrete harm it causes on mobile
(testability, leaks, recomposition/redraw cost). Then propose a target
design using the right pattern from this chapter.

Layer & dependencies: Keep each refactor step shippable—the app must
compile and pass tests after every step.

Deliverable: The diagnosis, the target design, and a numbered,
small-step refactor plan (each step independently safe), with the
before/after of the first step shown in full.