How can I find an S3 object key based on the filename that was uploaded

I have an s3 bucket that I am using for file storage with my PHP/Laravel application.

I have a certain case where I need to manually add a bunch of pdf's to a bucket in a given folder/prefix. I then need to run a csv import into my db. Part of the import is the pdf filenames.

For each iteration thought the csv import I want to use the known filename and go link the imported item to the pdf in S3.

I have been messing with this and have the AWS S3 SDK installed but I don't see a way of getting the object back from S3 based on a filename.

I am running: php 7.2 aws sdk v3.9 via composer

What I am currently testing is:

   $results = $s3->getPaginator('ListObjects', [
    'Bucket' => env('S3BUCKET'),
    'Prefix' => 'folder-name/'
]);


foreach ($results as $result) {
    foreach ($result['Contents'] as $object) {
        $doc = $s3->getObject([
            'Bucket' => env('S3BUCKET'),
            'Key'    => $object['Key']
        ]);
        dd($doc);

The issue here is that no filename is listed so I can't run a compare of any kind.

TIA

via Chebli Mohamed