laravel eloquent relationship polymorphic

问题

I have a polymorphic relationship, comments: (id, text, commentable_id, commentable_type ), images :(id, title) and videos :(id, title).

videos table has a many to many relationship with matters table.

I managed to recover the comments and their relationship such as the video but I cannot recover the title of the matter, passing from the comments table, after the videos table and then table of matters.

below my request.

class Comment extends Model
{
    public function commentable()
    {
        return $this->morphTo();
    }
}

class Video extends Model 
{
    public function comments()
    {
        return $this->morphOne(Comment::class, 'commentable');
    }

    public function matters()
    {
        return $this->belongsToMany(Matter::class, 'videos_matters');
    }
}

class Matter extends Model
{
    public function videos()
    {
        return $this->belongsToMany(Video::class, 'videos_matters');
    }
}

Request : 
        $comments = Comment::with('created_by')
            ->with('commentable.matters')       
            ->whereDate('created_at', '=', date('Y-m-d'))
            ->get();

来源：https://stackoverflow.com/questions/60873653/laravel-eloquent-relationship-polymorphic