Try Fettle for yourself

This boots a real WordPress site in your browser (via WordPress Playground), with the actual Fettle plugin installed and active. Two sample pages already contain real accessibility problems — missing alt text, an image link with no name, a file name used as alt text, a table whose header row is only bold text, low contrast, skipped headings, an unlabelled field, vague links — and the Fettle screen opens with them found. Click “Generate AI fix”, review the suggestion, then Apply or Discard it.