i have overridden my custom controller in etc/di.xml
<preference for="Magento\Catalog\Block\Product\ListProduct" type="Vendor\Module\Block\Catalog\Product\ListProduct" />
<preference for="ToolbarModel" type="Vendor\Module\Block\Catalog\Product\ProductList\Toolbar" /> <!--ToolbarModel: alias for Magento\Catalog\Model\Product\ProductList\Toolbar -->
<!--Override for Block catalog Search layer -->
<preference for="Magento\LayeredNavigation\Block\Navigation" type="Vendor\Module\Block\CatalogSearch\Layer" />
<!-- Override model: Catalog Resource-->
<preference for="Magento\Catalog\Model\ResourceModel\Product\Collection" type="Vendor\Module\Model\Catalog\Resource\Product\Collection" />
my etc/frontend/di.xml is as
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
<!--Override controller -catalogsearch-->
<preference for="Magento\CatalogSearch\Controller\Result\Index" type="Vendor\Module\Controller\CatalogSearch\ResultController" />