I'm not convinced you need React/Next.js even in those cases. Web components work and LLMs are so capable of using them that I find there is increasingly little utility in big frameworks.
You get the best of both worlds, better language than XML/HTML and yah, you can deliver only HTML since the consumer typically doesn't need all that JavaScript, spa stuff. The Island Architecture.
Feels like a good in-between. Good DX for me, great UX and mostly HTML with some JavaScript sprinkled and fallback for users.