chunk array and group a new one

<?php

$arr = [
        '001', 1, '002', 2, '003', 3, '004', 4
    ];
    
$result = [];
$groups = array_chunk($arr, 2);
foreach($groups as $group) {
    $result[] = [
            'id'    => $group[0],
            'num'   => $group[1],
        ];
}

print_r($result);