magento 2 admin - Changing default view per page from 20 to 1000 product / configurable product

[AsifJalil]

want to change current products / catalog view / Configurable Products from by default 20 view per page to 1000 views per page changes i have done in both files gird.phtml and extended.phtml but not working need your help its urgent, changes below i have done but not working . i have done changes on following files path of file

1. app/code/magento/backend/view/adminhtml/templates/widget/grid.phtml

2. app/code/magento/backend/view/adminhtml/templates/widget/grid/extended.phtml but non of these working need your help its very urgent. Thanks

Code

<option value="520"<?php if ($block->getCollection()->getPageSize() == 520): ?>
                      selected="selected"<?php endif; ?>>520
              </option>
         <option value="550"<?php if ($block->getCollection()->getPageSize() == 550): ?>
             selected="selected"<?php endif; ?>>550
               </option>
      <option value="700"<?php if ($block->getCollection()->getPageSize() == 700): ?>
        selected="selected"<?php endif; ?>>700
        </option>
     <option value="800"<?php if ($block->getCollection()->getPageSize() == 800): ?>
          selected="selected"<?php endif; ?>>800
         </option>
       <option value="1000"<?php if ($block->getCollection()->getPageSize() == 1000): ?>
          selected="selected"<?php endif; ?>>1000
                        </option>