Twig – Different Variables/Functions for one twig.html

Since 3 weeks i try to learn php with the symfony framework.
I want to build an application with which i can track my expanses.

I made good progress but since 2 days i have a little logic problem so maybe someone can help me here.

I want to make a dashboard.(the main side of the project) There the user can monitor the expenditures.
This works. Now i want also a form at the dashboard, so the user can add new expenditures. I already implement a form but with a extra route. So in my ExpenditureController i have the functions dashboard and the function addExpenditure which generate different twig.html templates.

So the user can monitor his expenditures with …budgetapp/expenditure/dashboard
and he can add new Expenditure with …budgetapp/expenditure/addexpenditure

My Dashboard-Function

    #[Route('/dashboard/', name: 'dashboard')]
public function dashboard(ExpenditureRepository $ar)
   {
    $user = $this->getUser();
    $expenditures = $ar-> findexpendituresOfUser($user);

    return $this->render('expenditure/dashboard.html.twig', [
    'expenditures' => $expenditures,
       ]);
}

The expenditure/dashboard.html.twig shows the Expentiures of the current user in a table

My addExpenditure-Function
public function addExpenditure (ManagerRegistry $doctrine, Request $request){

    $em = $doctrine->getManager();
    $expenditure = new Expenditure();
    $form = $this->createForm(ExpenditureType::class, $Expenditure);
    $form->handleRequest($request);

    if($form->isSubmitted()){
    $em->persist($expenditure);
    $em->flush();
    }

    return $this->render('expenditure/addexpenditure.html.twig', [
        'addexpenditureForm' => $form->createView()
    ]);
}

The expenditure/addexpenditure.html.twig looks like this:

{% block body %}
<div class="container">
{{form(eintragenForm)}}
</div>
{% endblock %}

---

My problem /mistake in thinking:
How can i implement the form to the dashboard? So of course i can take the code from the addexpenditure function and put it 1:1 in the dashboard-funciton. but i dont think this is the right way? I also tried to including template fragments with the offical Embedding Controllers Documentation of Symfony, but this also dont work.
So someone can help me with a suggestion how you would handle this in your project?

Best regards
Markus