Is React a good option to make a full-stack web app?

I want to make:

  1. a cryptic hunt website which involves authentication, a DB of questions and answers for the hunt, and security to prevent any compromise of the answers
  2. a dashboard for a competition which involves authentication and forms

Is React sufficient enough to make this or I will require Express as well?

React is only a front-end framework, so you’ll have to use Express + a database for the back-end, whether that’s MongoDB/Mongoose or some form of SQL (SQLite and PostgreSQL are commonly used with Node.js).

Thanks. So should I learn React first or Node.js(Express)?

depends on what you’re most comfortable with. I’d say go with React first, get an idea of how to set things up and then proceed with backend technologies.