How can I get the page from menu as posts?

Use wp_get_nav_menu_items to get the items from your menu.

Use wp_list_pluck to extract just the object_id from each menu item. This is the ID of the page the menu item refers to.

You’ll now have an array of the page IDs in the order they appear in the menu.

Create a new WP_Query for post_type page and pass that array as post__in argument, and set orderby to post__in.