Magento 2 Get all attributes option in phtml

$_objectManager = MagentoFrameworkAppObjectManager::getInstance();
    $col = $_objectManager->create('MagentoEavModelResourceModelEntityAttributeGroupCollectionFactory');
    $cole = $_objectManager->create('MagentoCatalogModelResourceModelProductAttributeCollectionFactory');
    
    $attributeSetId = 4; //Here is attribute set id
    $groupIds = [];
    $attributeids = [];
    $somearray=[];
        $groupCollection = $col->create()
        ->setAttributeSetFilter($attributeSetId)
        ->load(); // product attribute group collection
    foreach ($groupCollection as $group) {
        
        $groupAttributesCollection = $cole->create()
            ->setAttributeGroupFilter($group->getId())
            ->addVisibleFilter()
            ->addFieldToFilter('is_user_defined', array('eq' => 1))
                ->load(); // product attribute collection
       
        foreach ($groupAttributesCollection->getItems() as $attribute) {
            
            $opte=$attribute->getname();
            //echo "<strong>".$opte."</strong>";
            $opt=$attribute->getid();
            $options=$block->getattributeoptions($opt);
    
                  foreach($options as $values){
                  // echo $values['label'];
                }
        }
    }

By Factory Method :

You need to inject MagentoEavModelConfig in your construct

protected $eavConfig;
public function __construct(
    ...
    MagentoEavModelConfig $eavConfig,
    ...
){
    ...
    $this->eavConfig = $eavConfig;
    ...
}

then you can use that in your class

$attribute = $this->eavConfig->getAttribute('catalog_product', 'country');
$options = $attribute->getSource()->getAllOptions();

By Object Manager :

$objectManager = MagentoFrameworkAppObjectManager::getInstance();
$eavConfig = $objectManager->get('MagentoEavModelConfig');
$attribute = $eavConfig->getAttribute('catalog_product', 'country');

$options = $attribute->getSource()->getAllOptions(); // for attribute option.

Note : Don't use object manager direct.

The code which you have used only give those options which are selected on all products.'

You want to all option of a product attribute then you have to use below code:

Using OBject Manager:

$objectManager = MagentoFrameworkAppObjectManager::getInstance();
$eavConfig = $objectManager->create('MagentoEavModelConfig');
$attribute = $eavConfig->getAttribute('catalog_product', 'country');
$options = $attribute->getSource()->getAllOptions();

Using Injection

protected $eavConfig;
public function __construct(
    ...
    MagentoEavModelConfig $eavConfig,
    ...
){
    ...
    $this->eavConfig = $eavConfig;
    ...
}

public function getAllOption()
{
    attribute = $this->eavConfig->getAttribute('catalog_product', 'country');
    $options = $attribute->getSource()->getAllOptions();
}