What technologies to use in the Android application for the university?

Question

Android

Hello. My name is Nurbol. I need to create an application for a university. I am a beginner Android developer and I wanted to ask what technologies I should use. The application should have: SignIn/SignUp, chat(videoChat, textChat, and would like a video conference), and upload and download(lectures, books, etc.).
Questions:
1 What database to use to store data? (books, lectures, documents, drawings, etc.)
2 How can I do or what technology to use to create chats (video chat, just chat, conference).
I just started doing and I use Firebase(firestore) to store all the data and for signIn/singUp I use Firebase(Auth).
And for video chat I was advised WEBRTC (haven't tried it yet).
If possible, give good advice for the base, design, chat. (If possible, with links to documentation or tutorials).
And if you made such an application, could you send a link to github.
Thank you very much.