I'm trying to remove or hide dates / days from fullcalendar V5 for example I have these dates: 2021-09-10 and 2021-09-12 what I am trying to do is not to show the dates or events on that day.

    document.addEventListener('DOMContentLoaded', function () {
    var calendarEl = document.getElementById('calendar');
    var MyDate = new Date(2021, 9, 10);

    var calendar = new FullCalendar.Calendar(calendarEl, {
        initialView: 'timeGridWeek',
        locale: 'es',
        headerToolbar: {
            right: "timeGridWeek,timeGridDay,listWeek",
            center: "title",
            left: "prev,next"
        },

        // No muestro los fines de semana
        weekends: false,
        hiddenDays: [0, 6],

        // Hora minima y maxima en la que se van a mostrar los eventos, con 30 minutos de separacion
        timeFormat: 'H:mm',
        axisFormat: 'HH:mm',
        slotMinTime: '11:00',
        slotMaxTime: '21:00',

        dayRender: function (cell) {
            MyDate.css("visibility", "hidden");
            cell.css("visibility", "hidden");
        },

       events: [
          {
            url: 'alltwo.php', // use the `url` property
            color: 'red',
          }
        ],

        eventSources: [
            {
                url: 'all.php', // use the `url` property
                color: '#1c97df',    // an option!
                textColor: 'whitesmoke',  // an option!
                eventColor: '#378006',
                // method: 'POST',
                dataType: 'json',
            }
        ],
    });

    calendar.render();
});

The code is the one I am trying to use but it would not be working.

Version FullCalendar 5.9.0