I don’t think you can move “Posts” as it is a built in post type. You’d need to remove the admin menu for it and move it, but then it would be impossible to nest categeoris, tags and other links. Each post type should have it’s own top level menu.
You can put a CPT under an options page, i think this should still work https://github.com/Hube2/acf-filters-and-functions/blob/master/acf-options-page-w-cpt-children.php
