Remove Meta Boxes on Post & Page Edit Screens from "Astra" Theme and "Astra Pro" Plugin for users who are not Administrators, so Editors and below. Inspired by user question: https://www.facebook.com/groups/wpastra/permalink/367143130421624/ -- below Code Snippet should go into "Code Snippets" plugin at best (please avoid functions.php)!

astra-remove-metaboxes-for-nonadmins.php

<?php
/** Do NOT include the opening php tag */


add_action( 'do_meta_boxes', 'ddw_remove_astra_metaboxes_for_non_admins' );
/**
 * Remove Astra settings meta box for users that are not administrators
 *   Inspired by: https://www.facebook.com/groups/wpastra/permalink/367143130421624/?comment_id=367167440419193&comment_tracking=%7B%22tn%22%3A%22R1%22%7D
 *
 * @author David Decker - DECKERWEB
 * @link https://gist.github.com/deckerweb/0086ebfc130633625ecbfb3093ac1a0c
 */
function ddw_remove_astra_metaboxes_for_non_admins() {

	/**
	 * If current user has capability 'edit_theme_options' (Administrators do!) then stop running code
	 */
	if ( current_user_can( 'edit_theme_options' ) ) {
		return;
	}

	/** Remove meta boxes, if no Administrator: */
	remove_meta_box( 'astra_settings_meta_box', 'page', 'side' );	// Remove Astra Settings in Pages
	remove_meta_box( 'astra_settings_meta_box', 'post', 'side' );	// Remove Astra Settings in Posts

}  // end function

Very useful :)