Pushing an element in an array of array - node.js

Question

This is my schema...How can I push an element in an array of an array?
example: I've to insert an element in (patient.problems.feedback) in an already existing document. please help me how to code in node js-MongoDB
let Patient = new Schema({
patient: {
patientId: {
type: String,
required: false
},
name: {
type: String,
required: true
},
age: {
type: String,
required: true
},
gender: {
type: String,
required: true
},
city: {
type: String
},
phoneNumber: {
type: String,
min: 10,
max: 10
},
referredBy: {
type: String
},
createdAt: {
type: String
}
},
Problems: [{
problemId: {
type: String,
required: false
},
problem: {
type: String,
required: true
},
howLongSuffered: {
type: String
},
medicinesFollowed: {
type: String
},
createdAt: {
type: String
},
feedbacks: [{
feedbackId: {
type: String,
required: false
},
feedback: {
type: String,
required: false
},
updatedAt: {
type: String
}
}]
}]
})
**This is my controller
How can I update the existing document by pushing an element into the feedbacks
**
exports.addFeedbackDetailsForExistingProblem = async function(req, res) {
try {
let feedbackCreatedDate = new Date();
feedbackCreatedDate = feedbackCreatedDate.toDateString();
await patientModel.findById(req.params.id).then(async(result) => {
console.log(result + req.body.id);
await result.updateOne({ 'Problems._id': req.body.id }, {
$push: {
'Problems.feedbacks': {
'feedbacks.feedback': req.body.feedback,
'feedbacks.createdAt': feedbackCreatedDate
}
}
})
});
} catch (err) {
res.status(500).send("Something Went Wrong");
}
}