Using a mongo connection more than once returns Cannot use a session that has ended

I'm having an issue using Mongo, consider:

const mongoose = require('mongoose');

const CONFIG = {
    host: "localhost",
    port: 27017,
    db: "dev"
};

const url = `mongodb://${CONFIG.host}:${CONFIG.port}/${CONFIG.db}`;
const options = {
    useNewUrlParser: true, 
    useUnifiedTopology: true, 
    useCreateIndex: true 
};

const checkMongoConnection = async () => {
    return new Promise(async (resolve, reject) => {
        if (mongoose.connection.readyState === 1) {
            return resolve();
        }

        try {
            await mongoose.connect(url, options);
            return resolve();
        } catch(error) {
            console.log(error);
            reject(error);
        }
    });
};

const disconnectMongo = async () => {
    return new Promise(async (resolve, reject) => {
        try {
            await mongoose.disconnect();
            return resolve();
        } catch(error) {
            console.log(error);
            reject(error);
        }
    });
};

module.exports = {
    checkMongoConnection,
    disconnectMongo
}

And my database query is like so:

const User = require('./app/Models/User');
const { checkMongoConnection, disconnectMongo } = require(
    './app/util/mongo-connection-util'
);

const task1 = async () => {
    try {
        await checkMongoConnection();

        const user = await User
            .findOne()

            console.log(user._id);

        await disconnectMongo();
    } catch(error) {
        console.log(error);
    }
};

task1()
task1()

The issue is that if I call a query the database with the task1 call and then query again immediately I get the error Cannot use a session that has ended. If I just call the function once there is no issue.

I understand that this is because the connection is already in use, the code would work if I utilised await and performed the functions in a serial manner, waiting for the first one to finish before performing the next.

However I want to do database calls after a group of API calls, so it will be async at different times. Is it possible to achieve this or do all database calls have to be one after another?