NextJS for 2023?

I do know ReactJS.

Why should I learn NextJS in 2023? Is it worth it? Does it speed up the development process?

What's your opinion on NextJS + Vercel?

If you need to build an app then it does all the work for you! No reason to scaffold anything out these days.

At my company all new apps are built using Next, and there's pretty much no learning curve required. Its utterly straightforward.