The configuration looks correct.

• What do you see instead of login form?
  
• Do you see a regular logged-in selfoss view?
  
• Is there a logout button in the sidebar?
  
• Could you try applying the following change to the source code and sharing what the website prints?

--- a/controllers/Index.php
+++ b/controllers/Index.php
@@ -17,6 +17,10 @@ class Index extends BaseController {
      * @return void
      */
     public function home() {
+        var_dump(\F3::get('public'));
+        var_dump(\F3::get('auth')->enabled());
+        exit;
+
         // parse params
         $options = [];
         if (\F3::get('homepage') != '') {