getObject from S3 bucket and display in browser using AWS SSO and Typescript

I've been looking everywhere and can't seem to find an example that comes close. This is as close as I've gotten:

import {APIGatewayProxyEvent} from 'aws-lambda';
import AWS from 'aws-sdk';
const creds = new AWS.SharedIniFileCredentials({profile: 'dev'});
const S3 = new AWS.S3(creds);

import {Readable} from "stream";

export const handler = async (_event: APIGatewayProxyEvent):  Promise<Readable> => {

    const s3Params = {
        Bucket: "some-aws-s3-buckeet",
        Key: "some-folder/some-document.pdf"
    }

    return S3.getObject(s3Params).createReadStream();
}

After this, I'm getting the error:

InvalidAccessKeyId: The AWS Access Key Id you provided does not exist in our records.

I've logged into AWS using the following:

aws sso login --profile dev