Configuration Override System: https://www.drupal.org/docs/drupal-apis/configuration-api/configuration-override-system

ConfigExampleOverrides.php

<?php
// This file will reside in modules/custom/YOURMODULE/src/Config
namespace Drupal\custom_event\Config;

use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Config\ConfigFactoryOverrideInterface;
use Drupal\Core\Config\StorageInterface;

/**
 * Example configuration override.
 */
class ConfigExampleOverrides implements ConfigFactoryOverrideInterface {

  /**
   * {@inheritdoc}
   */
  public function loadOverrides($names) {
    $overrides = [];
    if (in_array('config_split.config_split.development', $names)) {
      $overrides['config_split.config_split.development'] = ['status' => TRUE];
    }
    return $overrides;
  }

  /**
   * {@inheritdoc}
   */
  public function getCacheSuffix() {
    return 'ConfigExampleOverrider';
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCacheableMetadata($name) {
    return new CacheableMetadata();
  }

  /**
   * {@inheritdoc}
   */
  public function createConfigObject($name, $collection = StorageInterface::DEFAULT_COLLECTION) {
    return NULL;
  }

}
?>

custom.services.yml

services:
  config_example.overrider:
    class: Drupal\custom_event\Config\ConfigExampleOverrides
    tags:
      - {name: config.factory.override, priority: 5}