I agree that maybe NextJS could do with more 'batteries' included, for things like Auth, and could do a better job for providing (lowercase H) hooks for client-side data fetching (given its existing get*Props APIs), but I think it's realtively wise for NextJS to not have much of a say for things like UI component libraries. I don't think it makes sense for NextJS to ship with like Bootstrap - I don't want to use it!

> Full-stack javascript sounds cool for small side projects but I want to have the freedom to write my backend in wathever technology I want

You do have this freedom though! Doing full-stack javascript is a choice you can make with that freedom.