I have 2 different Play Console accounts and each have a Stories app in them. Currently both of them are linked to same Firebase account (i.e. same database). I want to ask if this is ok or should I make a separate Firebase project for each app?
The short answer is, it depends.
If the two apps are identical or closely related (eg. an admin-only app that controls the flow of the client app), then yes, you'll want to configure both apps to use the same Firebase project so that they both have access to the same data.
Using the same Firebase project in multiple apps is pretty common, especially in the scenario outlined above as well as deploying to multiple platforms. Take, for example, an app that you have deployed on the web, iOS, as well as Android. These apps run on different platforms, but they are essentially the exact same app, with the exact same functionality. You don't want to be maintaining multiple projects containing duplicate data, so it's a good idea to connect different versions of the same app to the same Firebase project.
On the other hand, if these apps are not related at all (eg a quiz game and a social media app), then it doesn't make sense for them to be using the same Firebase project as the two apps are completely separate from one another. In this scenario, using the same project would lead to disorganized data, as well as making it potentially more difficult to secure and query as the apps have separate functions, and thus separate logic to control the flow of data.
It sounds like your use case falls into the first category. You have the same app on multiple Play Console accounts. You probably want the data to remain consistent between them, so you'd want to use a single Firebase project.