Codeigniter 4.2 Auto Routing weird thing happening

You can keep using the legacy autorouter and there should be no change. If you are having issues with your site after upgrade make sure you updated your spark and public/index.php files.
The new autorouting system is well documented, so definitely read the docs if you have not already. The gist of it is that you still don’t need to declare routes, but your controller methods must now include the name of the method: getUser(), postWidget(), getShowBlog()