How to update field value inside the collection?

Working with Data Node.js Frameworks
,
1

I want that if one operation inside the controller and i update the collection so then i want to call another mongodb collection (model) and then findby id and then inside it has field which has array of object so i want to changed inside that array of object where every object have the id as well i will share the code.

const payMonthlyInstallment = async (req, res) => {
  const contractDetails = await Contract.findById(req.params.id).populate("customer").populate({
    path : 'product',
    populate : {
      path : 'category'
    }
  });
 
  const investerEdit = contractDetails?.investor?.map(item => item.investorDetail.toString())
  const monthlyInstallment = ((((((contractDetails.product?.price - contractDetails.downPayment) * 25)/100) + (contractDetails.product?.price - contractDetails.downPayment)) / contractDetails.planOfInstallment) / investerEdit.length)

  investerEdit.map(async (item) => {
  const user =   await client.db("test").collection("investors").aggregate([
      { $match: { _id: ObjectId(item) } },

      ]).toArray()
    // const investor = Investor.findOne({_id: item});
    console.log("investerEdit", user)
    // const contracts = investor
  })
  console.log(monthlyInstallment ,investerEdit,investerEdit.length)
  res.send("contract");
}