I am developing a flutter app with node js backend and mongo database.

This is the post schema

const postSchema = new mongoose.Schema({
  userId: {
    type: String,
    required: true,
  },
  creator: {
    type: String,
    required: true,
  },
  createdAt: {
    type: Date,
    default: Date.now(),
  },
  title: {
    type: String,
    required: true,
  },
  breed: {
    type: String,
    required: true,
  },
  desc: String,
  price: {
    type: Number,
    required: true,
  },
  views: {
    type: Number,
    required: true,
    default: 0,
  },
  age: {
    type: String,
    required: true,
  },
  category: {
    type: [String],
    required: true,
  },
  phoneNo: {
    type: String,
    required: true,
  },
  images: {
    type: [String],
    required: true,
  },
  imagesThumb: {
    type: [String],
    required: true,
  },
  active: {
    type: Boolean,
    default: true,
  },
  location: {
    type: {
      type: String,
    },
    coordinates: [Number],
  },
  address: {
    type: String,
    required: true,
  },
  sold: {
    type: Boolean,
    default: false,
  },
});

I want to implement a fair randomization or rotation mechanism for displaying posts in my flutter app. So that each posts get a fair chance of being shown to a wide audience.

How should I change the schema to achieve this and how should the posts be fetched?