React Build Pages/Router/SEO/Sitemap

I have an react web app and it has routes like about,contact etc... When i type "x.x/route" to the browser i get "404 Not Found" but when i click to the link with the component i get the page and my url = "x.x/route" even i get 404 in manual type

And in sitemap.xml i do not receive the routes

So ... is there anyway to make it optimized for SEO or SITEMAP.XML ? or how can i make a build with folders