I personally don't find NextJS appealing at all. It's so over the top, felt like it was adding complexity for the sake of it. Maybe it's a "skill issue".

Ultimately this all boils down to 2 things:

* your/your team's proficiency in the tech

* using the right tool for the job

I am not sure if you're trying to replicate some specific NextJS feature or if you're just asking what tech to use for your backend? If it's the latter, Django/Flask/FastAPI will do just fine. More than fine. It's boring, but it works.

My go to would be a simple REST API backend + ReactJS on the frontend. If you want to start mixing server side generation then there is a way forward but it depends on the nature of your app.

Start simple. Keep it boring.