Please open project manager/cpm.php. In this file you will find this line at 385 $hook = add_menu_page( __( 'Project Manager', 'cpm' ), __( 'Project Manager', 'cpm' ), $capability, 'cpm_projects', array($this, 'admin_page_handler'), 'dashicons-networking', 3);. You can try to change the position. The number “3” is the menu position. Please change the position and it should be different from others.
It has worked, changed it to 30 and it shows at the bottom of post types. Have to admit this seems like a daft system in WordPress where you have to manually define a menu position in code, so much easier ways to handle that.