When using Unity WebGL, how do I download large file from a ubuntu server in an ec2 instance?

Question

I have to download large file(~5GB) from ubuntu server in an ec2 instance to Unity WebGl(Web Browser).

In Ubuntu server, I use NodeJS, express.

I was able to access files on the server through restapi (unity web request) and read file data successfully.

But, I can't download this data to file to local client(User PC).

I found how to download file from server like these.

• How To Work with Files Using Streams in Node.js : https://www.digitalocean.com/community/tutorials/how-to-work-with-files-using-streams-in-node-js
• Download a file from NodeJS Server using Express : Download a file from NodeJS Server using Express
• File Upload and Download in Node.js using Multer : https://medium.com/geekculture/file-upload-and-download-in-node-js-c524a8050c8f

They all say it can use

res.setHeader('Content-disposition', 'attachment; filename=' + filename);
res.setHeader('Content-type', mimetype);

var filestream = fs.createReadStream(file);
filestream.pipe(res);

or

res.download(file);

So, I wrote the code for the download as follows.

const doGetDownloadFile = (req, res, next) => {
var upload_folder = './uploads';
//var file = upload_folder + '/' + req.body.fileName;
var file = upload_folder + '/' + 'logs.txt';

    try {
        if (fs.existsSync(file)) { // 파일이 존재하는지 체크
            var filename = path.basename(file); // 파일 경로에서 파일명(확장자포함)만 추출
            var mimetype = mime.getType(filename); // 파일의 타입(형식)을 가져옴

            console.log(filename, mimetype);
            console.log(getDownloadFilename(req, filename));

            // res.download(file);

            res.setHeader('Content-Disposition', 'attachment; filename=' + getDownloadFilename(req, filename));
            res.setHeader('Content-type', mimetype);

            var filestream = fs.createReadStream(file);

            //filestream.on("data", () => process.stdout.write('.')).pipe(res);

            var stat = fs.statSync(file);
            var str = progress({
                length: stat.size,
                time: 100
            });

            str.on('progress', function(progress) {
                console.log(progress.percentage);
            });

            filestream.pipe(str).pipe(res).on('error', (err) => {
                console.log("Error Log In Server : ", err);
            }).on('finish', ()=> {
                console.log("Finish Log in Server");
            })

        } else {
            res.send('해당 파일이 없습니다.');
            return;
        }
    } catch (e) { // 에러 발생시        
        console.log(e);
        res.send('파일을 다운로드하는 중에 에러가 발생하였습니다.');
        return;
    }
}

This code works without errors, but there is a problem.

The file download percentage is increasing, but when I look at the response tab in the network window, there is nothing, and as a result, only the percentage is increasing, and I don't actually download the file from my browser.

I'm a web beginner, so I don't know much. What should I do now?