Create a sortable admin column for attachment (Media Library) file size. See https://cfxdesign.com/display-file-size-as-a-sortable-column-in-the-media-library/

add_initial_file_size_postmeta.php

<?php

// Adds initial meta to each attachment
function add_initial_file_size_postmeta($column_name, $post_id) {
  static $query_ran;

  if($query_ran !== null) {
    $all_imgs = new WP_Query(array(
      'post_type'      => 'attachment',
      'post_status'    => 'inherit',
      'posts_per_page' => -1,
      'fields'         => 'ids'
    ));
    $all_imgs_array = $all_imgs->posts;
    foreach($all_imgs_array as $a) {
      if(!get_post_meta($a, 'filesize', true)) {
        $file = get_attached_file($a);
        update_post_meta($a, 'filesize', filesize($file));
      }
    }
    $query_ran = true;
  }
}
add_action('manage_media_custom_column', __NAMESPACE__.'\\add_initial_file_size_postmeta');

sortable_filesize.php

<?php

// Ensure file size meta gets added to new uploads
function add_filesize_metadata_to_images($meta_id, $post_id, $meta_key, $meta_value) {
  if('_wp_attachment_metadata' == $meta_key) {
    $file = get_attached_file($post_id);
    update_post_meta($post_id, 'filesize', filesize($file));
  }
}
add_action('added_post_meta', 'add_filesize_metadata_to_images', 10, 4);

// Add the column
function add_column_file_size($posts_columns) {
  $posts_columns['filesize'] = __('File Size');
  return $posts_columns;
}
add_filter('manage_media_columns', 'add_column_file_size');

// Populate the column
function add_column_value_file_size($column_name, $post_id) {
  if('filesize' == $column_name) {
    if(!get_post_meta($post_id, 'filesize', true)) {
      $file      = get_attached_file($post_id);
      $file_size = filesize($file);
      update_post_meta($post_id, 'filesize', $file_size);
    } else {
      $file_size = get_post_meta($post_id, 'filesize', true);
    }
    echo size_format($file_size, 2);
  }
  return false;
}
add_action('manage_media_custom_column', 'add_column_value_file_size', 10, 2);

// Make column sortable
function add_column_sortable_file_size($columns) {
  $columns['filesize'] = 'filesize';
  return $columns;
}
add_filter('manage_upload_sortable_columns', 'add_column_sortable_file_size');

// Column sorting logic (query modification)
function sortable_file_size_sorting_logic($query) {
  global $pagenow;
  if(is_admin() && 'upload.php' == $pagenow && $query->is_main_query() && !empty($_REQUEST['orderby']) && 'filesize' == $_REQUEST['orderby']) {
    $query->set('order', 'ASC');
    $query->set('orderby', 'meta_value_num');
    $query->set('meta_key', 'filesize');
    if('desc' == $_REQUEST['order']) {
      $query->set('order', 'DSC');
    }
  }
}
add_action('pre_get_posts', 'sortable_file_size_sorting_logic');