Ask HN: Vite or NextJS?

I am building a new project from scratch. I have a backend already written in Python/FastAPI. I have React/Typescript experience with CRA and Vite (and I prefer the latter). I haven't used NextJS before, but I'm interested in learning more about it. I'm thinking of using it and figuring it out as I go along, but I'm wondering how much time I should expect this to set me back? If I'm already familiar with React, will NextJS take me a few hours to pickup? A few days? Weeks? I understand that this is a broad question and everyone has different capacity to learn, but I'm trying to get a rough sense since I don't want to push off deadlines too much.