Rename to match class

app/Ajax.php

+<?php
+
+namespace App;
+
+use App\Controllers\TemplateFaq;
+
+class Ajax {
+
+    public function __construct() {
+        add_action( 'wp_ajax_get_questions', [ $this, 'get_questions' ] );
+        add_action( 'wp_ajax_nopriv_get_questions', [ $this, 'get_questions' ] );
+    }
+
+    public function get_questions() {
+        // Check for nonce security
+        if ( ! wp_verify_nonce( $_POST['nonce'], 'ajax-nonce' ) ) {
+            die ( 'Nonce verification failed!' );
+        }
+
+        $category = isset( $_POST['category'] ) ? $_POST['category'] : null;
+        $keywords = isset( $_POST['keywords'] ) ? $_POST['keywords'] : null;
+        $out      = '<p>' . __( 'Sorry, no results were found.', 'kudos-website' ) . '</p>';
+
+        $templateFaq = new TemplateFaq();
+        $questions   = $templateFaq->questions( $category, $keywords );
+
+
+        if ( $questions->have_posts() ) :
+            $out = '';
+            while ( $questions->have_posts() ) : $questions->the_post();
+                $out .= template( "partials.content-faq" );
+            endwhile;
+        endif;
+
+        wp_send_json( $out );
+        wp_die();
+    }
+}
+
+new Ajax();