Display product quantity in cart and checkout

Paste the following code in the active theme’s functions.php:

/* if the product quantity is between X and X, display "plus que X en stock" in cart and checkout */
add_filter( 'woocommerce_cart_item_name', 'showing_stock_in_cart_items', 99, 3 );
function showing_stock_in_cart_items( $item_name, $cart_item, $cart_item_key  ) {
    // The WC_Product object
    $product = $cart_item['data'];

    if (empty($product)) {
        return $item_name;
    }

    // Get the stock
    $stock = $product->get_stock_quantity();

    // When stock doesn't exist
    if (empty($stock)) {
        return $item_name;
    }

   // display the stock
   if ($stock >= '1' && $stock <= '3') {     /* was ($stock <= '3') */
      $item_name .=" 
× " . $cart_item['quantity'] . "
" . '
'.__( "Plus que " .$stock. " en stock","woocommerce").'
';
   } else  {
       $item_name .=" 
× " . $cart_item['quantity'] . "
";
   }

    return $item_name;
}

Edit quantity (range) and text as needed.

Then, paste the following code in Appearance > Customize > Additional CSS:

/* remove native item quantity in checkout */
.woocommerce-checkout #order_review .product-quantity {
	display: none;
}

/* remove stock function quantity in cart and mini-cart*/
.woocommerce-cart .cart_item .function-product-quantity,
.woocommerce-mini-cart .function-product-quantity {
	display: none !important;
}

Source: https://stackoverflow.com/questions/59001052/woocommerce-show-stock-status-on-cart-page (+ additional edits made by myself)