I try to embed dynamically a form when field must be added under some condition

in formType

 // Add an event listener to the funding field to add/remove the employer field based on isCoordEmployer
        $builder->get('funding')->addEventListener(
            FormEvents::POST_SUBMIT,
            function (FormEvent $event) {
                $form = $event->getForm();
                $funding = $form->getData();
                
                if ($funding && $funding->isIsCoordEmployer()) {
                    $form->getParent()->add('employer', EmployerType::class);
                } else {
                    $form->getParent()->remove('employer');
                }
            }
        );

I tried everything i could i can’t add dynamically the fields

{{ form_row(form.employer.firstName) }}
{{ form_row(form.employer.lastName) }}
{{ form_row(form.employer.email) }}
{{ form_row(form.employer.nameOfCompany) }}

error says employer property is unknown

Of course if

->add('employer', EmployerType::class);

is not submitted to this condition, everything works fine.

I miss something. I need to be pointed in the right direction.
Thanks for any help.