I have the same problem (localhost on Windows, XAMPP, PHP 7.4.25).
Can’t access settings using direct link (/wp-admin/options-general.php?page=breadcrumb-navxt) and the is *no position* in menu to click in Settings / Breadcrumb NavXT.
One user with administrator role. Changed to “Twenty Nineteen” theme doesn’t change anything. The same with turning off all other plugins – problem still exists.
Please help!