Dynamic render view symfony5

I tried to do an dynamic render view in my website with dynamic url. I tried to write an function to do that.

    public function html(Name $formation, string $slug, Html $name): Response
    {
        if($formation->getSlug() !== $slug){
            return $this->redirectToRoute('html', [
                'id' => $formation->getId(),
                'slug' => $formation->getSlug(),
                'name' => $name->getName()
            ], 301);


        }
        return $this->render('html_css/'.$name.'.html.twig');
    }

All stuffs is in a database but when I tried to return the render $name got an issues : (Method '__toString' is not implemented for '\App\Entity\Html') but $name is an string

    public function getName(): ?string
    {
        return $this->name;
    }

So why I have this issues ?

Do you thinks they are better solution to do what I want ? I try to search on routing documentation of symfony but don't find what I wan't.

Thanks for your answer !