How to get only selected values of an attribute in listing page in Magento 2?

I am using Magento 2.3

I have created a custom attribute “Test model”(id: test_model).Attribute is Multiple select.Please see below code:

  $_productCollection = $block->getLoadedProductCollection();
   foreach ($_productCollection as $_product): ?>
     <?php $attributes = $_product->getAttributes();
        foreach($attributes as $a){ 
        <?php $name = $a->getName(); ?>
            <?php if(preg_match("/_model/", $name)){ 
                if($a != ''){ ?>
                    <p><?php echo $a->getName(); ?></p>
                <?php } ?>
            <?php } ?>
        <?php } ?>

     <?php endforeach; ?>

First I have called all product attributes after that I have added condition to display only the attribute which have “_model” in its name. Output for this code is as below:

Now I want to display all selected value of this attribute as well, So How can I achieve this?

Here attribute is displayed four times because current category contains 4 products. So is there any other way to display the attribute and value only one time?

NOTE: Remember that I want to show only those values of this attribute which are selected in product not all value