Allow same file ending on multiple PageType definitions and remove default index.html in TYPO3 Page configuration

config.yaml

routeEnhancers:
  PageTypeSuffix:
    type: CustomPageType
    default: .html
    index: index
    map:
      sitemap.xml: 1533906435
      product/|.html: 1603119111937

CustomPageTypeDecorator.php

<?php

declare(strict_types=1);

namespace VENDOR\Extension\Routing\Enhancer;


use TYPO3\CMS\Core\Routing\Enhancer\PageTypeDecorator;
use TYPO3\CMS\Core\Routing\RouteCollection;

class CustomPageTypeDecorator extends PageTypeDecorator
{
    public const IGNORE_INDEX = [
        '/index.html',
        '/index/',
    ];

    public const ROUTE_PATH_DELIMITERS = ['.', '-', '_', '/'];

    /**
     * @param \TYPO3\CMS\Core\Routing\RouteCollection $collection
     * @param array $parameters
     */
    public function decorateForGeneration(RouteCollection $collection, array $parameters): void
    {
        parent::decorateForGeneration($collection, $parameters);

        /**
         * @var string $routeName
         * @var \TYPO3\CMS\Core\Routing\Route $route
         */
        foreach ($collection->all() as $routeName => $route) {
            $path = $route->getPath();

            if (array_key_exists('type', $parameters)) {
                $mappings = array_flip($this->map);
                if (array_key_exists($parameters['type'], $mappings)) {
                    $splitPath = explode('|', str_replace(['.', '/'], ['\.', '\/'], $mappings[$parameters['type']]));
                    if (count($splitPath) == 2) {
                        $regEx = sprintf('/(.*)(\{.+\})(\/%s)(\|)(%s)/', $splitPath[0], $splitPath[1]);
                        $path = preg_replace($regEx, '$1$3$2$5', $path);
                        $route->setPath($path);
                    }
                }
            }

            if (true === \in_array($path, self::IGNORE_INDEX, true)) {
                $route->setPath('/');
            }
        }
    }

    public function decorateForMatching(RouteCollection $collection, string $routePath): void
    {
        foreach ($this->configuration['map'] as $checkPath => $typeNum) {
            $counts = 0;
            $regEx = str_replace('|', ')(.+)(', sprintf('/(.*)(%s)/', str_replace(['.', '/'], ['\.', '\/'], $checkPath)));
            $replaced = preg_replace($regEx, '$1$3/$2|$4', $routePath, -1, $counts);
            if ($counts > 0) {
                $routePath = $replaced;
            }
        }

        parent::decorateForMatching($collection, $routePath);
    }
}

ext_localconf.php

<?php


// register own PageTypeEnhancer
$GLOBALS['TYPO3_CONF_VARS']['SYS']['routing']['enhancers']['CustomPageType'] = \VENDOR\Extension\Routing\Enhancer\CustomPageTypeDecorator::class;