Ignores upload and content paths

The plugin ignores the WP_CONTENT_DIR and the UPLOADS constants.

To get options-general.php?page=webpc_admin_page to stop complaining I made some changes:

diff -Nurp -Z a/app/Media/Htaccess.php b/app/Media/Htaccess.php
--- a/app/Media/Htaccess.php	2020-08-13 16:10:12.942727988 +0200
+++ b/app/Media/Htaccess.php	2020-08-13 16:20:40.910026632 +0200
@@ -17,7 +17,7 @@
 
     public function addRewriteRulesToWpContent($isActive)
     {
-      $path = dirname(apply_filters('webpc_uploads_path', ''));
+      $path = WP_CONTENT_DIR;
       if (!$isActive) return $this->saveRewritesInHtaccesss($path);
 
       $values = apply_filters('webpc_get_values', []);
diff -Nurp -Z a/app/Settings/Paths.php b/app/Settings/Paths.php
--- a/app/Settings/Paths.php	2020-08-13 16:10:12.942727988 +0200
+++ b/app/Settings/Paths.php	2020-08-13 16:29:53.052319231 +0200
@@ -4,12 +4,14 @@
 
   class Paths
   {
-    private $pathUploads  = 'wp-content/uploads';
-    private $pathOutput   = 'wp-content/uploads-webpc';
+    private $pathUploads;
+    private $pathOutput;
     private $dirsExcluded = ['.', '..', '.git', '.svn', 'node_modules'];
 
     public function __construct()
     {
+      $this->pathUploads = wp_upload_dir()['basedir'];
+      $this->pathOutput = $this->pathUploads . '/webpc';
       add_filter('webpc_uploads_path',   [$this, 'getUploadsPath'],  0,   2);
       add_filter('webpc_uploads_webp',   [$this, 'getOutputPath'],   0,   2);
       add_filter('webpc_uploads_path',   [$this, 'parsePath'],       100, 2);
@@ -36,10 +38,13 @@
 
     public function parsePath($value, $skipRoot = false)
     {
-      if ($skipRoot) return trim($value, '\/');
+      if ($skipRoot) return trim($value, '/');
 
+      if($value[0] === '/') {
+          return '/' . trim($value, '\/');
+      }
       $path = apply_filters('webpc_uploads_root', ABSPATH);
-      return $path . '/' . trim($value, '\/');
+      return $path . '/' . trim($value, '/');
     }
 
     public function getPrefixPath($value)

In our setup we have /wp, /content, and /uploads, so the content dir isn’t the parent of uploads, and wp isn’t a parent of content.
so the sugested filter didn’t work.