Using multiple db in one project

I am not sure if should i create multiple databases or not. But I think multiple db would create better data.
So I want to create a app, where users can post the link for a particular concept and other users can upvote/downvote it.

so here users can post a link(blog, article) for useState concept.
I want, if I hit /react/useState then it should go in react database and go in useState collection and show me all the documents available. It can be /react/useRef meaning → react database and useRef collection.

same for /javascript/optionalChaning → javascript database and optionalChaining collection and return all documents inside it.

How can I achieve this using multiple databases

go to that particular db then go into that particular collection?