我有一个项目在magento和进口的产品是做同样的方式，因为你想要的。我们采取了csv与10列或更多，但我们只出口数量和SKU在这种情况下。
这里我们所做的

<?php 

    // downloaded file path
    $filesRoot = BP.'/pub/path/to/your/folder/';

    //If folder doesn't exist, create it
    if (!file_exists($filesRoot)) {
        mkdir($filesRoot, 0777, true);
    }

    //their file
    $fileIn = $filesRoot.'5dkmiglm.csv';

    //your file
    $fileOut = $filesRoot.'pricelist_206876.csv';

    $url = 'https://cdn.sandberg.world/feeds/5dkmiglm.csv';

    //Download their csv in your environment
    if(!file_put_contents($fileIn, file_get_contents($url))) {
        die('errore download file');
    } 

    $countLine = 0;
    $fileInOpn = fopen($fileIn, 'r');
    $fileOutOpn = fopen($fileOut, 'w');
    while (($line = fgetcsv($fileInOpn)) !== FALSE) {     

        //position of each column
        if($countLine==0){
            $keyQty = array_search('qty', $line);
            $keySku = array_search('sku', $line);
        }
        $newLineRev = [];
        foreach ($line as $key => $el) {
            if ($key == $keyQty || $key == $keySku) {
                $newLineRev[$keyQty] = $line[$keyQty];
                $newLineRev[$keySku] = $line[$keySku];
                continue;
            }
        }

        // Write in your file
        fputcsv($fileOutOpn, $newLineRev);
        $countLine++;
    }
    fclose($fileInOpn);
    fclose($fileOutOpn);