[wereHamster]

This is why I created timvir (https://timvir.vercel.app). It really doesn't take much more than a few custom components that you can compose in MDX files to create documentation pages. The timvir blocks are whatever I needed at that time, a lot of them are still experiments, others I use regularly. Since MDX, Timvir are just React in the end, I can even show, document, test interactive components. It's probably not as convenient as SB at this point though.

Since Timvir is basically just a component library and not a build tool on its own, integrating it is quite easy, and won't break whenever you upgrade Next.js, Webpack etc. That was one my my main motivations: tools that come with their own build system are hard to make, and even harder to make reliable. You are buying convenience in the short term, but getting pain in the long term.