ordenar divs con jquery

// Ordena los productos ascendentemente y descententemente //

$('.container_loader').hide();

    var product = $('.producto');

    function order_motorcycle(){ // Ordenar ascendentemente //
    product.sort(function(a, b){
    return a.textContent > b.textContent ? 1 : -1;
    }).appendTo('.right_section');
    } order_motorcycle();

    $('#order_products').change(function(){
    
    $('.container_loader').fadeIn().delay(2000).fadeOut();
    product.animate({opacity: 0},0 ).delay(3000).animate({opacity: 1}, 2000); // <-- aqui es donde necesitas cambiar el efecto fade por opacity //
    

    if($('option:nth-of-type(2)').is(':selected')){
    
    product.sort(function(a,b){ // Ordena descendentemente //
    return a.textContent < b.textContent ? 1 : -1;
    }).appendTo('.right_section');
    } else {
    order_motorcycle();
    }
      });
      
      function buscar() {
    var buscador = $('#buscador').val().toLowerCase();
    var not_found = true;
    var listCategory = '';
    $('.producto span').each(function () {
        var name_products = $(this).text().toLowerCase();
        if (name_products.indexOf(buscador) !== -1) {
            var category_products = $(this).parents('.producto').attr('category');
            $(this).parents('.producto').show();
            not_found = false;
            listCategory += category_products; 
            //Concateno todo lo que se vaya a mostrar en una sola variable y la valido al final.
        }
        else {
            $(this).parents('.producto').hide();
        }

        if (!not_found) {
            $('#text').hide();
        } else {
            $('#text').show();
            $('.btn-check').prop('checked', false);
        }

    });
    if (listCategory.length > 0) {//Aqui hare la validación de tus checkbox
        $('.btn-check').each(function () {
            var check = $(this).attr('category');
            if (listCategory.indexOf(check) !== -1) {
                $(this).prop('checked', true);
            } else {
                $(this).prop('checked', false);
            }
        });
    }
}
$('#buscador').on('keypress', function (e) {
    if (e.keyCode == 13) {
        buscar();
    }
});

// Buscador //
$('#button_search').on('click', function () {
    buscar();
});

// Casillas checkbox //
$('.btn-check').prop('checked', true);
$('#apply_filter').on('click', function () {
    $('.producto').hide();
    $('#text').hide();
    $('.btn-check:checked').each(function () {
        var input_category = $(this).attr('category');
        $('.producto[category*="' + input_category + '"]').show();

    });
});

$('#all').on('click', function () {

    if ($('#all').is(':checked')) {
        $('.btn-check:not(#all)').prop('checked', true);
    } else if ($('#all').not(':checked')) {
        $('.btn-check:not(#all)').prop('checked', false);
    }

});
    

body{
display: flex;
}
.left_section{
width: 30%;
background: #cdcdcd;
}
.left_section select{
display: block;
margin: auto;
font-size: 1.65em;
}
.right_section{
width: 70%;
background: #ededed;
display: flex;
flex-wrap: wrap;
justify-content: center;
position: relative;
}
.producto{
width: 25%;
text-align: center;
background: #cdcdcd;
display: table;
}
img{
width: 100%;
}
.container_loader{
display: none;
position: absolute;
width: 100%;
text-align: center;
top: 50%;
}
.loading{

display: flex;
justify-content: center;
align-items: center;
}
.loader{
width: 35px;
height: 35px;
background: transparent;
border-radius: 50%;
border: 3.5px solid;
border-right-color: #CDCDCD;
border-top-color: #CDCDCD;
border-bottom-color: #CDCDCD;
animation: spin .5s linear infinite;
margin-right: 1%;
}
@keyframes spin {
0%{
    background-color:transparent;
    transform: rotate(360deg);
}
    }
#text{
font-size: 2vw;
position: relative;
padding: 25%;
display: none;
}
.category{
display: block;
}
.category input,
.category label{
cursor: pointer;
font-size: 1.25rem;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<aside class="left_section">

    <select id="order_products">
        <option>Ordenar ascendentemente</option>
        <option>Ordenar descendentemente</option>
    </select>
    <input type="text" id="buscador" placeholder="Buscar moto..." maxlength="36">
    <button id="button_search">Buscar</button>
    <span class="category"><input type="checkbox" class="btn-check" id="all" category="all"><label for="all">All</label></span>
    <span class="category"><input type="checkbox" class="btn-check" id="verde" category="verde"><label for="verde">moto de color verde</label></span>
    <span class="category"><input type="checkbox" class="btn-check" id="rojo" category="rojo"><label for="rojo">moto de color rojo</label></span>
    <span class="category"><input type="checkbox" class="btn-check" id="blanco" category="blanco"><label for="blanco">moto de color blanco</label></span>
    <span class="category"><input type="checkbox" class="btn-check" id="gris" category="gris"><label for="gris">moto de color gris</label></span>
    <span class="category"><input type="checkbox" class="btn-check" id="negro" category="negro"><label for="negro">moto de color negro</label></span>
    <button id="apply_filter">Aplicar filtro</button>

</aside>

<aside class="right_section">

<div class="producto" category="all gris"><img src="https://www.formulamoto.es/elementosWeb/gestionCajas/FOM/Image/2018//kawasaki-ninja-H2R.jpg"><span>Moto Rfa 2000</span></div>

<div class="producto" category="all verde"><img src="https://www.formulamoto.es/elementosWeb/gestionCajas/FOM/Image/2018//kawasaki-ZX-10RR_g.jpg"><span>Sudora KFI</span></div>

<div class="producto" category="all blanco"><img src="https://as.com/betech/imagenes/2017/10/13/portada/1507918164_397427_1507918224_noticia_normal.jpg"><span>Z-moto 6000 turbo</span></div>

<div class="producto" category="all negro"><img src="https://www.crmotos.com/motocicletas/formula/bajacilindrada/sport/sportx200/fotos/1M.jpg"><span>Hirasc 300k</span></div>

<div class="producto" category="all rojo"><img src="https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcTt-wqMoSBYFaR6dIJE9a02yMmQJl6AUYrYnQ&usqp=CAU"><span>Az Mini-Inferno 10000</span></div>

<div class="producto" category="all gris"><img src="https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcSAk-Q8UCYkf4YBLwh6QZr1yx-gB8mbn0Hh9Q&usqp=CAU"><span>Droma T legacy</span></div>

<div class="producto" category="all blanco"><img src="https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcRcHyCIrQoZjVqudofBdi_qh9wGiRJfdpbZxw&usqp=CAU"><span>KazaQ Op</span></div>

<div class="producto" category="all negro"><img src="https://www.crmotos.com/motocicletas/formula/bajacilindrada/sport/sportx200/fotos/1M.jpg"><span>Marine T-5000</span></div>

<div class="container_loader">
<div class="loading">
    <div class="loader"></div>
    <p>Cargando productos...</p>
</div>
</div>

<p id="text">No se encontraron resultados...</p>

</aside>