When I rename the htaccess.txt file to .htaccess, my site errors terribly. It is the supplied core htaccess. Any ideas why?

Frontend failure:

Attempted to load class "Helper" from namespace "HelixUltimate\Framework\Platform".
Did you forget a "use" statement for another namespace?
Exceptions 2Stack Traces 2
Symfony\Component\ErrorHandler\Error\
ClassNotFoundError
in .../public_html/templates/shaper_helixultimate/error.php (line 19)
use Joomla\CMS\Uri\Uri;use Joomla\CMS\Language\Text;$app = Factory::getApplication();$doc = Factory::getDocument();$template = Helper::loadTemplateData();$params = $template->params;$fontCSS = '';function addGoogleFont($fonts){
require()
in .../public_html/libraries/src/Document/HtmlDocument.php (line 721)
HtmlDocument->_loadTemplate('.../public_html/templates/shaper_helixultimate', 'error.php')
in .../public_html/libraries/src/Document/HtmlDocument.php (line 776)
HtmlDocument->_fetchTemplate(array('template' => 'shaper_helixultimate', 'directory' => '.../public_html/templates', 'debug' => true, 'csp_nonce' => null, 'templateInherits' => '', 'params' => object(Registry), 'file' => 'error.php'))
in .../public_html/libraries/src/Document/HtmlDocument.php (line 612)
HtmlDocument->parse(array('template' => 'shaper_helixultimate', 'directory' => '.../public_html/templates', 'debug' => true, 'csp_nonce' => null, 'templateInherits' => '', 'params' => object(Registry), 'file' => 'error.php'))
in .../public_html/libraries/src/Document/HtmlDocument.php (line 630)
HtmlDocument->render(false, array('template' => 'shaper_helixultimate', 'directory' => '.../public_html/templates', 'debug' => true, 'csp_nonce' => null, 'templateInherits' => '', 'params' => object(Registry), 'file' => 'error.php'))
in .../public_html/libraries/src/Document/ErrorDocument.php (line 139)
ErrorDocument->render(false, array('template' => 'shaper_helixultimate', 'directory' => '.../public_html/templates', 'debug' => true, 'csp_nonce' => null, 'templateInherits' => '', 'params' => object(Registry), 'file' => 'error.php'))
in .../public_html/libraries/src/Error/Renderer/HtmlRenderer.php (line 78)
HtmlRenderer->render(object(ParseError))
in .../public_html/libraries/src/Exception/ExceptionHandler.php (line 126)
ExceptionHandler::render(object(ParseError))
in .../public_html/libraries/src/Exception/ExceptionHandler.php (line 72)
ExceptionHandler::handleException(object(ParseError))
in .../public_html/libraries/src/Application/CMSApplication.php (line 322)
CMSApplication->execute()
in .../public_html/includes/app.php (line 61)
require_once('.../public_html/includes/app.php')
in .../public_html/index.php (line 32)
ParseError
syntax error, unexpected '|', expecting variable (T_VARIABLE)



System Info:
PHP Built On Linux c16611.sgvps.net 5.15.126-MCIclouder399 #399 SMP PREEMPT Wed Aug 16 16:53:17 EEST 2023 x86_64
Database Type mysql
Database Version 5.7.44-48-log
Database Collation utf8mb4_general_ci
Database Connection Collation utf8mb4_general_ci
Database Connection Encryption None
Database Server Supports Connection Encryption Yes
PHP Version 8.1.27
Web Server Apache
WebServer to PHP Interface cgi-fcgi
Joomla! Version Joomla! 4.4.3 Stable [ Pamoja ] 20-February-2024 16:00 GMT
User Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36