Both are good, but if it's hard to you to use NextJS, then you should go with SSR rendering. (Btw, there is a good article about using Next for SEO purposes https://prismic.io/blog/seo-with-react-and-nextjs)
If you want to use react, you are concerned about SEO, and you're just building a blog, I recommend you build a static site instead of a full-stack express app. Gatsby
is a good tool for this, and i've also had success with a tool called react-snap
. Whenever you update your blog content, you just rebuild and redeploy your static site to a service like Netlify.
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If you're not sure what I mean by a "static site" in this context and how it differs from an express app, this explanation might be helpful. Good luck and have fun!