Magento2 Product Grid – Display Custom Text-Field Attribute

You can just keep below code reference to get all option of attribute,

Inside your block file,

<?php
    protected $eavAttributeRepository;

    public function __construct(
        \Magento\Catalog\Block\Product\Context $context,       
        \Magento\Eav\Api\AttributeRepositoryInterface $eavAttributeRepository
    ) {
        parent::__construct($context);
        $this->eavAttributeRepository = $eavAttributeRepository;
    }

    public function getOptionlist($attributeCode){
        $attributes = $this->eavAttributeRepository->get(\Magento\Catalog\Api\Data\ProductAttributeInterface::ENTITY_TYPE_CODE,$attributeCode);
        $options = $attributes->getSource()->getAllOptions(false);
        return $options;                
    }

}
?>

Inside your phtml file,

<?php
    $optionList = $block->getOptionlist('power_types');
    foreach ($optionList as $value) {
        //print_r($value);
       echo $value['label'];
    }
?>

You need to do this changes,

Change your xml like this,

<referenceBlock name="product.info.main">
    <block class="Magento\Catalog\Block\Product\View" template="Magento_Catalog::product/view/more_info.phtml"></block>
</referenceBlock>

And modify your phtml file :

mytheme\Magento_Catalog\templates\product\view\more_info.phtml


<?php $_product = $block->getProduct(); ?>
<?php echo $_product->getAttributeText('more_info') ?>

OR

<?php $_product = $block->getProduct(); ?>
<?php echo $_product->getResource()->getAttribute('more_info')->getFrontend()->getValue($_product) ?>