React PWA renders on client side rather than Server although i'm using CloudFlare Workers

I’m working on react pwa that is currently on client side. i want to make it server side rendering enabled. I came across cloudflare workers, it serves static html. My page (index.html) has some scripts that downloads some js and css and then inject in my index.html. When i use cloudflare i assume it would serve me fully server rendered page, but it is rendered on client side. Any suggestion will be appreciated