#fleeting a half-baked metaphor:
Tools like Next.js is more akin to styled-components (replace with whatever flavour of CSS in JS you've touched). I've been using express.js since 2010, Next.js since 2016. I keep coming back to both, in fact, I'm using express.js (directly) way less frequently. I've build large SaaS projects with both.
But, every time I dig out an express.js project I know instantly where to go and how to get there. With Next.js, I have to re-learn how to use it.