It is not easy to hide the CMS from Theme detectors. You need to change all WordPress common paths in the source code, change the paths and links to the WordPress CMS, restrict access to WordPress common paths and files, and more.
If you have a WordPress site and you want to hide the fact that you’re using a WordPress CMS, install the WP Ghost plugin and configure it to hide and protect your website at the same time.
Read More: Hide Your Site From Theme Detectors and Hackers Bots