I'm very biased towards Python. I'm working on AutoML tools (created MachineLearning-as-a-Service web-service and open-source AutoML Python package). That's why I'm using Django. In my opinion it is very powerfull. There are for sure many people looking for easy start in Django+React setup, that's why I started writing tutorials.

fully agree - and in my first comment i do mention that if you are doing anything in math, then you NEED+HAVE to stay in python. No choice - even if you love javascript ;)

I've bought a number of templates over the course of a year building my company's website.

The general result is that the code quality is very low and the class names are not specific enough, so you get bogged down in css when you try to customize things.

Fool me once ... fool me twice ... fool me three times ...

But these templates you've linked to are frontend focused. Next doesn't really address the backend much at all. Most of what it does backend wise is to help the frontend (such as SSR).

If I needed a full webapp spun up quickly (db, auth, api emails, etc), I'd choose Django before Next.

well YMMV, but nextjs is fairly complete.

e.g. https://nextjs.org/commerce

here's one with Firebase auth, graphql, everything already setup https://themeforest.net/item/livani-react-next-ecommerce-sto...

Don't get me wrong, I like and use Next. But from what I can understand, it's just not as complete as Django, Rails, etc. I think the fact that template is using Firebase for its storage says a lot.

Next itself does not help you with Firebase or databases or any kind of persistent storage. It's entirely left up to you. That's a huge difference from Django, Rails, etc. The same is true of auth and many other things.

The nextjs one uses a third party (bigcommerce) as the back end.

Firebase is also a third party backend.

Any recommendations on one where you can own the backend yourself, like Django? Without composing all the pieces manually?

I'm currently running a Django backend, Vue frontend, and think Django is a fine tool -- but occasionally look for a nice cohesive Django alternative in the JS world.