Returning null item for no reason

You have a bad coding-style !!!

Change it !!! —> And you will have less problems !!!

import wixData from 'wix-data';
const collectionName2 = 'MyAll2';

$w.onReady(async()=> {   

    //Step-1:getting filter-data....
    let filteredData = await filterAction();
    //Step-2: ---> feeding repeater ...
    $w('#productList1').data = filteredData;
    //Step-3: reacting when repeater got its data...

    $w('#productList1').onItemReady(async ($item, itemData) => {
        if (itemData.product.discountedPrice == itemData.product.price) {
            $item('#discountBox2').hide();
            $item('#discount2').hide();
        } else {
            $item('#discount2').text = String(100 - Math.round(100 * itemData.product.discountedPrice / itemData.product.price)) + "% off";
        }
        const actualProduct = await wixData.query(collectionName2)
            .include('brand')
            .eq('product', itemData.product._id)
            .find()
            .then((res) => {
                let items = res.items;
                if (items.length > 0)
                    return items[0];
                else
                    return null;
            });
        if (actualProduct && actualProduct.brand) {
            if (actualProduct.brand.logoblack.startsWith('http://') || actualProduct.brand.logoblack.startsWith('https://') || actualProduct.brand.logoblack.startsWith('wix:image://')) {
                $item('#logo1').src = actualProduct.brand.logoblack;
            }
        } else {
            console.error("Error: Cannot read 'logoblack' property from undefined or null object.");
        }
        $item('#colors1').text = itemData.color.length + " colors";
        if (itemData.ecoFriendly == true)
            $item('#ecoFriendlySign3').expand();
        if (itemData.sustainable == true)
            $item('#sustainableSign3').expand();
    });

    //What the hell is productList? Box? Dropdown, apple, banana, a car?
    //DEFINE your element-IDs the right way!!!
    // It is a REPEATER --> then also declare it as a REPEATER inside of your code!!!!
    // ---> repProductList <--- GOOOOOOOOOOOD !!!!!
    
    
    // and again APPLE & BANANAS ????? You know what i mean!!!
    //$w('#gender').onChange(async () => {
    
    $w('#gender').onChange(async () => {
        if ($w('#genderDecorBackButton').checked == true)
            $w('#genderDecorBackButton').checked = false;
        else
            $w('#genderDecorBackButton').checked = true;
        await buildFiltersAndPopulateRepeater()
    });
});

async function filterAction() {
    let dataQuery = wixData.query(collectionName2);
    if ($w('#gender').checked == true) {  
        dataQuery = dataQuery.hasSome('gender', 'Women');
    } else {
        dataQuery = dataQuery.hasSome('gender', 'Men');
    }    
}