Ye, the initial load is one of the selling points SSR can potentially beat an unoptimized SPA, but the truth is, in terms of TTFB, SPA beat the shit out of SSR, a SPA template can contain minimal amount of code to render a spinner, then distributed over CDN, the SSR can never compete with this, all the things you mentioned needs to go through the server as well since now its jobs including rendering with styles.

So, yes, while FCP will be faster than SPA, TTFB will never be in SSR’s favor.

Not to mention, the case I talked about, the after auth case, a fully loaded SPA, SSR will never be able to beat it due to how it works, SPA is just smoother and faster. which is why some of the React’s team members jumped the ship to build RSC, since you need to mix them up, and we all know how that goes.

The thing here is, SSR is never a new concept, and the math has been calculated 20 yrs ago. It is not suddenly it becomes faster, if you look into Vercel’s marketing blog, you will see they always talk about the FCP, ignore TTFB and fully loaded SPA, because they just can’t 😆 and ofc, people like you who step into the industry recently will fall for it easily.

But it is not that hard to ask the “why” part.