I see many samples and videos on how to do firebase for mobile and they call this "multiplatform". However, I don't see much on the desktop. There is one video on firebase flutter Windows by using a web and it seems to work. However, I do not see any tutorials for both mobile and desktop. Firebase would be a great example on syncing between desktop and mobile. We have such an app in development right now. Desktop development is new, but I'm surprised how little there is.
There is a library called firebase_dart, but the documentation seems weak.