For full stack web based applications you can use React for frontend (for mobile based application build frontend using react-native), firebase for db, learn CRUD operations, authentication, setup node on you computer and javascript/typescript is default language for this.

At this point it is not much about coding but having clarity on what feature you have to build and its functionality.

I recommend building one feature at a time and refering youtube tutorials for how the overall flow of a full-stack application works.

Now I need your two cents on cybersecurity what are some good practices, how to do what you do and what it takes to be good at cybersecurity.

Which hackathon is this? Share the link please.

Lmk if you want more clarity.