How to remove /category/ from URL (wordpress + polylang)

I am using the Polylang plugin and want to remove /category/ from the URL.

Before I installed the plugin, I used this:

add_filter('category_link', function($a){ return str_replace( 'category/', '', $a ); }, 99 );

It works for the main language, but it doesn't work for language versions. For example:

site.com/blog/ - works, response code 200
site.com/de/blog/ - not working, response code 404
site.com/de/category/blog/ - works, response code 200

I want both pages (site.com/blog/ and site.com/de/blog/) to work. How do I do that?

You'll need to adjust your filter to account for the language prefix. Here's an example of how you might modify your filter to work with Polylan like the following

add_filter('category_link', function($a){
    $current_language = pll_current_language();

    if ($current_language && $current_language !== pll_default_language()) {
        return str_replace('/category/', '/' . $current_language . '/', $a);
    } else {
        // If it's the default language, just remove 'category/'
        return str_replace('/category/', '/', $a);
    }
}, 99);