Multi-site - Setup.php not working

I am attempting to get multi-site working (sub_directory) and have implemented setup.php. In this case, I am sharing the themes and plugins between the multiple sites, located in user/sites. The setup.php is being called, I can see output in my browser.

Here’s the setup.php. I’ve added php logging to the browser console so I can see what’s going on.

<?php
/**
 * Multisite setup for sub-directories or path based
 * URLs for subsites.
 *
 * DO NOT EDIT UNLESS YOU KNOW WHAT YOU ARE DOING!
 *
 * Modified Sept 2020 to share themes and plugins folders across
 * subsites.
 */

function console_log($output, $with_script_tags = true) {
    $js_code = 'console.log(' . json_encode($output, JSON_HEX_TAG) . 
');';
    if ($with_script_tags) {
        $js_code = '<script>' . $js_code . '</script>';
    }
    echo $js_code;
}

use Grav\Common\Filesystem\Folder;

// Get relative path from Grav root.
$path = isset($_SERVER['PATH_INFO'])
   ? $_SERVER['PATH_INFO']
   : Folder::getRelativePath($_SERVER['REQUEST_URI'], ROOT_DIR);

// Extract name of subsite from path
$name = Folder::shift($path);
$folder = "sites/{$name}";
$prefix = "/{$name}";

console_log("subsite info:");
console_log("path: {$path}");
console_log("name: {$name}");
console_log("folder: {$folder}");
console_log("user/folder: user/{$folder}");
console_log("prefix: {$prefix}");

if (!$name || !is_dir(ROOT_DIR . "user/{$folder}")) {
    console_log("\$name is not defined for \$folder does not exist");
    return [];
}

// Prefix all pages with the name of the subsite
$container['pages']->base($prefix);

// default paths for themes and plugins
$themes = ["user/themes"];
$plugins = ["user/plugins"];

// is there a themes folder in the subsite? 
// if so, prepend default array with subsite themes path
//if (is_dir(__DIR__ . "/user/{$folder}/themes")) {
//  array_unshift($themes, "user/{$folder}/themes");
//}

// is there a plugins folder in the subsite? 
// if so, prepend default array with subsite plugins path
//if (is_dir(__DIR__ . "/user/{$folder}/plugins")) {
//  array_unshift($plugins, "user/{$folder}/plugins");
//}

$retval = [
    'environment' => $environment,
    'streams' => [
        'schemes' => [
            'user' => [
               'type' => 'ReadOnlyStream',
               'prefixes' => [
                   '' => ["user/{$folder}"],
               ]
            ],
            // set theme path for subsite
            'themes' => [
              'type' => 'ReadOnlyStream',
              'prefixes' => ['' => $themes]
            ],
            // set plugins path for subsite
            'plugins' => [
              'type' => 'ReadOnlyStream',
              'prefixes' => ['' => $plugins]
            ]
        ]
    ]
];

$msg = print_r($retval, true);
console_log("returned: {$msg}");
return $retval;

And here is my console output from what is returned.

returned: Array
(
    [environment] => <mywebsite url>
    [streams] => Array
        (
            [schemes] => Array
                (
                    [user] => Array
                        (
                            [type] => ReadOnlyStream
                            [prefixes] => Array
                                (
                                    [] => Array
                                        (
                                            [0] => user/sites/actin5
                                        )

                                )

                        )

                    [themes] => Array
                        (
                            [type] => ReadOnlyStream
                            [prefixes] => Array
                                (
                                    [] => Array
                                        (
                                            [0] => user/themes
                                        )

                                )

                        )

                    [plugins] => Array
                        (
                            [type] => ReadOnlyStream
                            [prefixes] => Array
                                (
                                    [] => Array
                                        (
                                            [0] => user/plugins
                                        )

                                )

                        )

                )

        )

)

It looks good, but I get these errors, as if the stream mapping is not working.

Any ideas as to what I’m missing or doing wrong?