This plugin checks the title of a new post/page or any other post type for uniqueness. The plugin provides a filter
unique_title_checker_arguments, which enables you to modify the
WP_Query arguments used to find duplicate titles. You may use it so search in more than only current post type for a duplicate title.
This is plugin is an enhancement of the Duplicate Title Checker by ketanajani which only supports posts but not pages or custom post types.
Maybe because the installation process is relatively simple, the official website does not write a detailed installation process for the time being. If you encounter problems installing this plugin, you can solve it through search engines or comment below, I will try to help you solve it
Plugin official website address
If you encounter problems in using the Unique Title Checker plugin, you can comment below, and I will try my best to help you solve the problem