Adding entities in a OneToMany relationship

Question

I am trying to make an application using Spring Boot, MySQL and HTML, but I have a problem. I have two entities, called Establecimiento and Valoracion. My idea is that an establishment can have multiple ratings, but a rating only belongs to one establishment. Therefore, a OneToMany relationship. I attach here how I have it in both entities:

....
@OneToMany(mappedBy = "establecimiento", cascade = CascadeType.PERSIST)
    private List<Valoracion> valoraciones;

    public void addValoracion(Valoracion valoracion) {
        valoraciones.add(valoracion);
        valoracion.setEstablecimiento(this);
    }

....
    @ManyToOne
    @JoinColumn(name = "establecimiento_id")
    private Establecimiento establecimiento;

Once the entities are established, I want to implement it in the controllers, but the problem is that for an establishment, every time I add a new valuation, it replaces the previous one, so I only have one valuation that is being rewritten. I leave the code below that I have in the controller to make the GET and POST requests.

    @RequestMapping(value="/cliente/establecimientos/{id}/nuevaValoracion", method = RequestMethod.GET)
    public String nuevaValoracion(@PathVariable Integer id, ModelMap model) {
        Establecimiento establecimiento = establecimientoRepository.findById(id).orElse(null);
        Valoracion valoracion = new Valoracion(); // crea una nueva instancia de Valoracion
        
        model.put("valoracion", valoracion); // agrega la valoración al modelo
        model.put("establecimiento", establecimiento);
        return "Cliente/añadirValoracion.html";
    }
    

    @RequestMapping(value="/cliente/establecimientos/{id}/anadirValoracion", method = RequestMethod.POST)
    public String anadirValoracion(@Valid Valoracion valoracion, @PathVariable Integer id, BindingResult bindingResult, ModelMap mp) throws JSONException {
        if (bindingResult.hasErrors()) {
            return "Cliente/añadirValoracion.html";
        } else {
            Establecimiento establecimiento = establecimientoRepository.findById(id).orElse(null);

            valoracion.setEstablecimiento(establecimiento);
            establecimiento.addValoracion(valoracion);

            establecimientoRepository.save(establecimiento);
            valoracionRepository.save(valoracion);
            mp.put("valoracion", valoracion);
            return "redirect:/cliente/establecimientos/" + id;
        }
    }

I have tried to do this and it only rewrites the valuation. The idea would be that every time you fill in the rating form, a new rating associated with the id of that establishment is added.

Any help would be appreciated.