magento2 – How to add an option to disable delivery time slot in Magento 2

Im pretty new to magento and to get myself on track , I decided to build an entire deliverydate module by myself , my module’s almost finished but whatever I do , I cant seem to build an option to Disable the Time slot. A helping hand would be a loootttt appreciated. FYI My timeperiod is json encoded and displays like this.
enter image description here

<?php

class DateOff extends AbstractFieldArray
{

protected $elementFactory;
public $_tslotList;

public function __construct(
    Context $context,
    Factory $elementFactory,
    array $data = ()
) {
    $this->elementFactory = $elementFactory;

    parent::__construct($context, $data);
}

/**
 * Initialise form fields
 *
 * @return void
 */
public function _construct()
{
    $this->addColumn('date_off', (
        'label' => __('Date'),
        'size' => __('40'),));
    $this->addColumn('tslot', (
                'label' => __('Time Slot'),
                'size' => __('40'),
                //'renderer' => $this->getTslotList(),
          ));

    $this->_addAfter = false;

    parent::_construct();
}

public function getTslotList()
{   
    $db =$this->db1('core_config_data');
    $sql = "SELECT value FROM core_config_data where config_id=60";
     //AND value LIKE '%(^0-9a-zA-Z() -._/:=,)%'";
    $result =($db('connection')->fetchAll($sql));
    $res = json_decode($result(0)('value'));

    echo '<pre>';
    print_r($res);
    exit();
    echo '</pre>';

}

public  function db1($tbl_name){

    $objectManager = MagentoFrameworkAppObjectManager::getInstance(); // Instance of object manager
    $resource = $objectManager->get('MagentoFrameworkAppResourceConnection');
    $connection = $resource->getConnection();
    $tableName = $resource->getTableName($tbl_name);
    return $db = (
        'connection' => $connection,
        'tableName' => $tableName,
    );
}
  

/**
 * Render array cell for prototypeJS template
 *
 * @param string $columnName
 *
 * @return mixed|string
 * @throws Exception
 */
public function renderCellTemplate($columnName)
{   
    if (!empty($this->_columns($columnName)) && in_array($columnName, ('date_off', 'tslot'))) {
        switch ($columnName) {
            case 'date_off':
                $element = $this->elementFactory->create('date');
                $element->setForm($this->getForm())
                    ->setName($this->_getCellInputElementName($columnName))
                    ->setHtmlId($this->_getCellInputElementId('<%- _id %>', $columnName))
                    ->setFormat('dd/m/yy');
                return str_replace("n", '', $element->getElementHtml());
            case 'tslot':
                $element = $this->elementFactory->create('hidden');

                $db =$this->db1('eav_attribute');
                $sql = "SELECT attribute_code FROM eav_attribute";
                $result =($db('connection')->fetchAll($sql));
                echo "<select>"; 
                //echo "optionsCaption: $t('-- Please select a delivery time--')";
                for($i=1;$i<=24; $i++){
                // I PUT THIS HERE TO CHECK WHETHER I CAN MAKE A DROPDWON USING SQL
                $res($i) = $result($i)('attribute_code');
                echo "<option value=$res($i)>$res($i)</option>";

                }
                echo "</select>"; 
                        $element->setForm($this->getForm())
                        ->setName($this->_getCellInputElementName($columnName))
                        ->setHtmlId($this->_getCellInputElementId('<%- _id %>', $columnName));
                return str_replace("n", '', $element->getElementHtml());
                break;
            default:
                break;
        }
    }

    return parent::renderCellTemplate($columnName);
}

/**
 * @return string
 */
public function getAddButtonLabel()
{
    return $this->_addButtonLabel;
}

}