How to update an array in Mongoose JS - mongodb

Question

Currently, I'm trying to create a Discord bot that will save a to-do list in a database. To do so, I wanted to use an array that contains any items the person adds by typing !listadd (something) that will then be stored in a MongoDB database. However, while this seems to work for Strings, I cannot seem to change an array at all using this method.
await list.findOneAndUpdate({_id: id},{$push:{todoList: msg}, itemToAdd:msg},{upsert : true})
This line above is what I'm using to update the list. While the change to itemToAdd is reflected perfectly in the database, nothing is pushed to todoList. I can't even seem to update todoList at all past setting what the default value is in the schema. (Like, if I put {todoList:['one','two']} as the update object, it still won't do anything)
I've tried using the .updateOne() method and, again, it works fine for itemToAdd, but nothing happens to todoList. I've also tried using the .markModified() method and I've either used it wrong or it isn't working here because, still, nothing changes in the database.
Full Code:
const mongoose = require('mongoose');
const todoSchema = new mongoose.Schema({
todolist : [String],
_id: {
type : String,
required : true
},
itemToAdd:{
type: String,
required: false
},
indexOfItemToRemove:{
type: Number,
required: false
}
});
const list = mongoose.model('list', todoSchema);
module.exports = async (client) => {
client.on('message', async (message) => {
const { author } = message;
const { id } = author;
const { bot } = author;
if (!bot){
console.log('AUTHOR:', author);
if (message.content.includes('!listadd ')){
const msg = message.content.substring(9)
await list.findOneAndUpdate({_id: id},{$push:{todoList: msg}, itemToAdd:msg},{upsert : true})
message.reply('Entry Added!')
}
if (message.content.includes('!listget')){
let doc = await list.findOne({_id:id})
message.reply(doc.itemToAdd)
}
}
})
}