Hello,
I use embedding controller to render on the same page 2 twigs :
the first twig renders every review
the second twig renders the form to submit a review. This is done with {{ render(path('app_new_review',{id:product.id})) }}

    #[Route('/newreview/{id}', name: "app_new_review")]
    public function newreview(Product $product,Request $request,EntityManagerInterface $entityManager):Response
    {
     $avis = new Review();
...
        $form = $this->createForm(AvisType::class,$avis);
        $form->handleRequest($request);
        if ($form->isSubmitted() && $form-> isValid()){
            $entityManager->persist($avis);
            $entityManager->flush();
            return $this->redirectToRoute('app_avis',['id'=>$product->getId()]);
        }
        return $this->renderForm('review/_form.html.twig', [
            'reviewform' => $form,
        ]);
     }

is correct. I tried it on an independant page and it works.

But when I put with "all reviews" twig, it won't submit.
Actually, I tried dd("foo"); in the newreview function but it seems that the function isn't executed.

I d like to keep the embedded system so that my "indexreview" function and my allreviews twig are not overloaded.

Can someone help me figuring out how to use/submit a form included in twig with render(path()) ?