WordPress - Deny access for admin pages

funcstions.php

<?php
add_filter( 'init', 'exclude_pages_from_normal_admin' );
function exclude_pages_from_normal_admin() {
    global $pagenow;

    $deny_pages = array(
        'edit.php',
        'update-core.php',
        'upload.php',
        'edit-comments.php',
        'themes.php',
        'customize.php',
        'theme-editor.php',
        'plugins.php',
        'tools.php',
        'import.php',
        'export.php',
        'options-general.php',
        'options-writing.php',
        'options-reading.php',
        'options-discussion.php',
        'options-media.php',
        'options-permalink.php'
    );

    $current_user = wp_get_current_user();
    if ( $current_user->ID != 1 && is_admin() && in_array( $pagenow , $deny_pages ) ) {
        wp_redirect( admin_url() );
    }
}

add_action( 'admin_menu', 'remove_menus' );
function remove_menus() {
    $current_user = wp_get_current_user();
    if ( $current_user->ID != 1 && is_admin() ) {

        $deny_pages = array(
            'edit.php',
            'edit.php?post_type=page',
            'update-core.php',
            'upload.php',
            'edit-comments.php',
            'themes.php',
            'customize.php',
            'theme-editor.php',
            'plugins.php',
            'tools.php',
            'import.php',
            'export.php',
            'options-general.php',
            'options-writing.php',
            'options-reading.php',
            'options-discussion.php',
            'options-media.php',
            'options-permalink.php'
        );

        foreach ($deny_pages as $key => $value) {
            remove_menu_page( $value );
        }
    }
}