Making a newsfeed sharing database structure

I'm creating a newsfeed system where in users can post and share posts.

What I got so far is:
Database Structure
tbl_post:id, user_id, ...
tbl_shared_post:id, post_id, shared_by

Post Retrieval Query : Eloquent

public function feedgetpost(Request $request) {        //Pluck the IDs of the current user's followers        $followers = UserFollower::where('status', 'accepted')            ->where('target_user_id', $currentUserID)            ->pluck('follower_id')->toArray();        //Pluck the IDs of the current user's followings        $followings = UserFollower::where('status', 'accepted')            ->where('follower_id', $currentUserID)            ->pluck('target_user_id')->toArray();        $feed= Feed::where('is_delete', 0)            ->whereIn('user_id', array_merge($followers, $following, [$request->user_id])) //Get following/followers post as well            ->limit(10)            ->orderBy('id', 'DESC')            ->get();        $arrays = [];        foreach ($feed as $post) {                $post['shares'] = PostShare::getSharesByPostID($post->id);                $arrays[] = $post;            }        }    return $arrays;}

But the code above returns data in this way:

{    caption: "This is a test upload only. Have fun :)!"    created_at: "2021-02-16T08:11:55.000000Z"    id: 1    is_delete: 0    shares: [        {'id':0, 'post_id': 1, 'shared_by': 3},        {'id':1, 'post_id': 1, 'shared_by': 5},        {'id':2, 'post_id': 1, 'shared_by': 14}    ]}

Now, based on the result set. I can't really render the shared post but only get the count of it.

My question is that, How do I make it so that:
Scenario 1.OP post something.
Scenario 2.User B shared OP's post, and then a share count of 1 gets credited to OP's post.
Scenario 3.User C shared User B's shared post, and a share count of 1 gets credited to User B's post.

and so on...