I do not see frontend accessibility as a separate task to review at the end, but as part of building the interface correctly from the start. Labels, focus, DOM order and contrast affect the real product, not just a checklist.
Many of the most important improvements are small ones: proper headings, visible focus states, solid keyboard navigation and avoiding components that depend only on hover. They are simple decisions, but they have a strong effect on the overall experience.
Working on accessibility usually improves the frontend in broader ways too. A more semantic, consistent and well-structured interface tends to be easier to maintain and easier to understand for everyone.