Capture an order status change and change the change_date value in a database table

I need a hand with a development that I am doing for my work which I have been working for a week and I cannot move forward.
My task consists of an Observer to capture the moment when an order changes status and in a given table change the value of date_of_modification.
Here is my code:

<?php

namespace MovistarAdminExportsObserver;

use MagentoFrameworkEventObserverInterface;
use MagentoFrameworkEventObserver;
use MovistarAdminExportsModelExportForAnalysis;
use MagentoSalesModelResourceModelOrderCollectionFactory;
use MovistarAdminExportsModelResourceModelExportForAnalysisRM;
use PsrLogLoggerInterface;


class SalesOrderStateChangeBefore implements ObserverInterface
{
    /**
     * @var ExportForAnalysis
     */
    protected $_exportForAnalysis;

    /**
     * @var LoggerInterface
     */
    protected $_logger;

    /**
     * @var ExportForAnalysisRMCollectionFactory
     */
    protected $_exportForAnalysisCollectionFactory;

    /**
     * @var ExportForAnalysisRM
     */
    protected $_exportForAnalysisResource;

    /**
     * @var CollectionFactory
     */
    protected $_collectionFactory;

    /**
     * SalesOrderStateChangeBefore constructor.
     * @param ExportForAnalysis $exportForAnalysis
     * @param LoggerInterface $logger
     * @param ExportForAnalysisRMCollectionFactory $exportForAnalysisCollectionFactory
     * @param CollectionFactory $collectionFactory
     */
    public function __construct(
        ExportForAnalysis $exportForAnalysis,
        LoggerInterface $logger,
        ExportForAnalysisRMCollectionFactory $exportForAnalysisCollectionFactory,
        ExportForAnalysisRM $exportForAnalysisResource,
        CollectionFactory $collectionFactory
    )
    {
        $this->_exportForAnalysis = $exportForAnalysis;
        $this->_logger = $logger;
        $this->_exportForAnalysisCollectionFactory = $exportForAnalysisCollectionFactory;
        $this->_exportForAnalysisResource = $exportForAnalysisResource;
        $this->_collectionFactory = $collectionFactory;

    }

    /**
     * @param MagentoFrameworkEventObserver $observer
     * @return SalesOrderStateChangeBefore
     * @throws Exception
     */
    public function execute(Observer $observer)
    {
        $order = $observer->getEvent()->getOrder();
        if ($order->getStatus() == 'processing' || $order->getStatus() == 'aprobado_mp' || $order->getStatus() == 'canceled' || $order->getStatus() == 'complete' || $order->getStatus() == 'closed'){
            $exportForAnalysisCollection = $this->_exportForAnalysisCollectionFactory->create();
            $exportForAnalysisCollection->addFieldToFilter('pedido_magento', [ 'in' => $order->getData('increment_id')]);
            $timezone = 'America/Argentina/Buenos_Aires';
            $timestamp = time();
            $dateTime = new DateTime("now", new DateTimeZone($timezone));
            $dateTime->setTimestamp($timestamp);
            $this->_exportForAnalysis->setData('fecha_de_modificacion', $dateTime->format('d-m-Y'));
        }
    }

}

Aca mi events.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="sales_order_state_change_before">
        <observer name="movistar_adminexports_sales_order_state_change_before" instance="MovistarAdminExportsObserverSalesOrderStateChangeBefore" />
    </event>
</config>

The problem is that I change the status of an order and in the table called export_for_analysis that has a date_of_modification column, the date is not updated as it should.
From already thank you very much!!!
Desde ya muchas gracias!!