_core-admin-email-confirm.php

<?php

/*
 * Plugin Name: Disable admin email confirmation
 * Plugin URI: https://github.com/szepeviktor/wordpress-website-lifecycle
 */

add_filter(
    'admin_email_check_interval',
    '__return_zero',
    PHP_INT_MAX,
    0
);

// Hard-code maintainer email address.
/*
add_filter(
    'pre_option_admin_email',
    static function () {
        return 'admin@szepe.net';
    },
    PHP_INT_MAX,
    0
);
add_filter(
    'pre_option_new_admin_email',
    static function () {
        return 'admin@szepe.net';
    },
    PHP_INT_MAX,
    0
);
*/