Automatic ARIA via accessible_rails gem versus manual content_tag markup for Rails form fields

Goal: ensure that form fields generated by Rails helpers meet WCAG 2.1 AA keyboard and screen‑reader requirements by providing appropriate ARIA attributes and live error messages.

Constraint: developers must decide between letting the accessible_rails gem inject ARIA attributes automatically based on model validations or writing explicit markup with content_tag and inline ARIA. The gem reduces boilerplate but adds a dependency and may conflict with JavaScript frameworks that manage their own accessibility state; manual markup offers full control but increases verbosity and the chance of inconsistent attributes across the application.

Which approach yields better long‑term maintainability in a codebase that already uses Stimulus controllers? How does each option affect compatibility with existing JavaScript‑driven widgets that set ARIA state? What level of test coverage is needed to guarantee that automatically generated attributes stay in sync with model validation changes?