symfony 5 Can't get a way to read the property "tipoinvitado" in class
tipoinvitado is not a property of Evento. If you want to add form fields that are not properties of the form data class simply add 'mapped' => false to your field.
->add('tipoinvitado', ChoiceType::class, array( 'label' => 'Prioridad', 'mapped' => false, 'choices' => array( 'VIP' => 'VIP', 'Empresa' => 'Empresa' ) ))