I'm new to Mongo and my database is **so slow**, it's nested several layers deep and ~35mB - how can I improve performance?

My schema: { "_id": { "$oid": "63d93fdb0ede25417d71d10f" }, "slug_nam - Pastebin.com - ignore random_slug, I can’t release the data definition names.

How I populate it:

    const dataDefinitions = await this.getDataDefinitions();

    for (let i = 0; i < 10; i++) {
      const district = this.createFakeDistrict();
      const territory = this.createFakeTerritory();
      for (let j = 0; j < 75; j++) {
        for (let k = 0; k < 3; k++) {
          territory.schools[j].projects[k].data =
      const createdTerritory = new this.territoryModel(territory);
      district.territory = createdTerritory;
      const createdDistrict = new this.districtModel(district);

How I call the data (Using Nest.js + Mongoose)

  async findAll() {
    return this.districtModel.find().populate('territory');

What can I do to speed things up? Right now, with a realistic data load (~35mB), it takes two seconds to load. I need to get that number down to less than 1 second - so what can I do? Is there a better design for my db? Is there some sort of indexing I should be doing? Some MongoDB setting I can change?