Route's base path for subdirectories

Question

I have the following structure:

/home/
    alvaro/
         public_html/
             Code Playground/
                 SlimTest/
                     logs/
                     public/
                     src/
                     templates/
                     vendor/
                     ...

http://example.com points to /home/alvaro/public_html, thus http://example.com/Code Playground/SlimTest points to /home/alvaro/public_html/Code Playground/SlimTest, directory on which I've placed this .htaccess file:

<IfModule mod_rewrite.c>
    RewriteEngine on
    RewriteRule ^$ public/ [L]
    RewriteRule (.*) public/$1 [L]
</IfModule>

In short, loading http://example.com/Code Playground/SlimTest in the browser executes my /home/alvaro/public_html/Code Playground/SlimTest/public/index.php Slim/3.9.0 (slim/slim-skeleton) entry point.

My problem is that I can't get routes right. I've tried every conceivable combination:

$app->get('/Code Playground/SlimTest', …);
$app->get('/Code Playground/SlimTest/', …);
$app->get('/Code Playground/SlimTest/public', …);
$app->get('/', …);
// …

... but I always get the 404 Not Found page delivered by Slim's NotFound class.

1. Is there a way to get base path upon route definition so I can prepend it in get()?

2. If not, what would a hard-coded path look like?

3. Should I look for a fix in Apache, such as Alias?