Firebase restructure and Flutter changes

I have a flutter app using Firebase that needs its structure worked on. With the current model it uses it would be like this


if there are 120 users as subscriber / follower, and 1 user make 1 posting, 120 duplicated postings will be added for a user’s main feed

and if the user update the posting, 120+1 datas should be updated.

I need this changed in Firebase and in the Flutter coding.

I need this done as soon as possible and here’s a link https://medium.com/firebase-tips-tricks/how-to-reduce-firestore-costs-8cb712473e83 givomg an example of what I need done

Thx