I have multiple apps in my project. I want to demonstrate the data from all of these apps in one dashboard. For example if event_1 happens 3 times in app_1 and 4 times in app_2 the dashboard shows that event_1 happened 7 times.
I need a user friendly dashboard with a GUI (I know that BigQuery is an option, but it does not provide charts and is not easy to manipulate parameters).
Update Since May 2018 Google Analytics for Firebase has the ability to show analytics across all apps in the project, in addition to its previous ability to show analytics for each individual app.
Old answer:
Firebase Analytics shows the data for each app separately.
It currently does not have the ability to report across multiple apps in a project.
That is a reasonable feature request though, so you should definitely report it here.