Symfony 6 - Class declared in services.yaml not found - php

Question

I have a problem with registering a class as a service in services.yaml.
I have created a class MenuBuilder.php in Symfony 6 that looks somewhat like this.
src/Menu/MenuBuilder.php
namespace App\Menu;
class MenuBuilder
{
public function createMainMenu(array $options)
{
// method logic
}
}
Now, when I want to register it as a service: (and use it in twig with KnpMenuBundle)
config/services.yaml
parameters:
services:
_defaults:
autowire: true # Automatically injects dependencies in your services.
autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
App\:
resource: '../src/'
exclude:
- '../src/DependencyInjection/'
- '../src/Entity/'
- '../src/Kernel.php'
app.menu_builder:
class: App\Menu\MenuBuilder
arguments: [ "#knp_menu.factory" ]
tags:
- { name: knp_menu.menu_builder, method: createMainMenu, alias: main }
I get an error Class "App\Menu\MenuBuilder" not found.
I tried making some other classes (ex. Test/TestClass) and namespaces and it doesn't work with freshly created classes.
On the other hand it i fiddled around with the naming and it recognized my entities and factories.
I tried clearing the cache
I am in development mode
I am getting this message when calling {{ knp_menu_render('main') }} in twig.
My composer autoload:
"autoload": {
"psr-4": {
"App\\": "src/"
}
},
symfony console debug:container app.menubuilder gives me this:
Information for Service "app.menu_builder"
==========================================
---------------- -------------------------------------------------------------
Option Value
---------------- -------------------------------------------------------------
Service ID app.menu_builder
Class App\Menu\MenuBuilder
Tags knp_menu.menu_builder (method: createMainMenu, alias: main)
Public no
Synthetic no
Lazy no
Shared yes
Abstract no
Autowired yes
Autoconfigured yes
Usages knp_menu.menu_provider.lazy
---------------- -------------------------------------------------------------
! [NOTE] The "app.menu_builder" service or alias has been removed or inlined when the container was compiled.
How do i get Symfony to recognize my classses?