Magento 2 Attributes – How to Remove or Delete an Attribute from Default Template

You can't update the default attributes in magento. If you want to change the default value of weight attribute then you can execute following query:

UPDATE `eav_attribute` SET `default_value` = '2' WHERE `eav_attribute`.`attribute_code`='weight';

You can remove it by adding the following code to the app/code/MyVendor/MyModule/Setup/InstallData.php file of your module (make sure to change the my_attribute value).

<?php

namespace MyVendor\MyModule\Setup;

use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;

class InstallData implements InstallDataInterface
{
    private $eavSetupFactory;

    public function __construct(EavSetupFactory $eavSetupFactory)
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }

    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
        $eavSetup->removeAttribute(
          \Magento\Catalog\Model\Product::ENTITY,
            'my_attribute');
    }
}

Hope it helps.

Purge cache and deploy static content by running the following commands.

php bin/magento cache:flush
php bin/magento setup:static-content:deploy -f