In general Next.js has so many layers of abstraction that 99.9999% of projects don't need. And the ones that do are probably better off building a bespoke solution from lower level parts.
Next.js is easily the worst technology I've ever used.
I recently rewrote my auth to use better-auth (as a separate service), which has allowed me to start moving entirely off Next.js (looking at either React Router 7 or Tanstack Router).
Back when I started, Next.js made server side rendering incredibly easy, but it turns out I didn't need it. My marketing site is entirely static, and my app is entirely client rendered.
And I have some use cases where I want to have a headless crm/api “hidden” behind the front end. So in these cases using next as a backend proxy works well for me.
Tanstack seems to be following Next.js in that they’re just over complicating everything and their docs felt lacking for the most of their features.
Sadly tan stacks releases a new version every other day and react router was complete 5 versions ago but cannot seem to keep changing the api to stay relevant in the never ending js relevancy ending war.