We don’t recommend serving your frontend from the public folder as if you have multiple pages (or even just a SPA) you will hit issues due to koa-router not being aware of those routes (especially with SPAs)
Strapi is headless meaning it’s designed to run on it’s own not integrated with a frontend into one node process. Generally we only suggest a single page (index.html) to be used in the public folder, usually for things like a meta refresh redirect.
Your frontend should be hosted separately and call the Strapi APIs over REST or GraphQL.