Copy this following code and save as disable_email.php . Then place that file in "wp-content/plugins/" directory. And active from Admin Panel.

<?php
/*
Plugin Name: Stop email change password
Description: Whatever
*/

if ( !function_exists( 'wp_password_change_notification' ) ) {
    function wp_password_change_notification() {}
}
?>

Copy this following code and save as disable_email.php . Then place that file in "wp-content/plugins/" directory. And active from Admin Panel.

<?php
/*
Plugin Name: Stop email change password
Description: Whatever
*/
        
if (!function_exists('wp_password_change_notification')) {
    function wp_password_change_notification($user) {
        return;
    }
}
?>