Even that really requires some nuance. If most of your site is static with a small amount (in terms of data) dynamic content, it could easily be faster to split

Even that really requires some nuance. If most of your site is static with a small amount (in terms of data) dynamic content, it could easily be faster to split things up into 2 phases: load the static part and then do a single REST request to get the dynamic part for client side rendering. The first time the user ever visits your page, it will take a small hit compared to SSR, but in subsequent visits the browser can easily cache the static part so it only needs to query for cache coherence (which should be very cheap in terms of throughput) and obviously the REST query for the dynamic parts. If you do SSR, the client is much more limited in terms of caching because the page contents is not constant. In my opinion, SSR is actually more for slow CPUs than for slow networks since you can make the network usage for client side rendering very efficient as well, but client side rendering will always be worse in terms of client CPU.