Yes but they obsess over making everything perfectly ssr to the point of both delivering slow and half the time making client side navigations slow as hell after the user is already past the pay walled/marketing material part of your app.

Honestly except for the marketing page and blogs and stuff, most apps are fine without server rendering. In fact I'd say many that avoid server rendering actually feel better simply because next.js makes it really easy to screw up your performance doing it.