search.php

<?php

// @link https://searchwp.com/documentation/multisite/
global $post;

$current_blog_id = get_current_blog_id();

get_header();

if ( have_posts() ) {
	while ( have_posts() ) {
		the_post();

		// Search Results may be formatted as SearchWP results
		// because we're searching cross-site on the main site.
		if ( 1 === $current_blog_id ) {
			if ( $current_blog_id !== $post->site ) {
				switch_to_blog( $post->site );
				$post = get_post( $post->id );
				get_template_part( 'search-result' );
				restore_current_blog();
			} else {
				$post = get_post( $post->id );
				get_template_part( 'search-result' );
			}
		} else {
			get_template_part( 'search-result' );
		}
	}
} else {
	get_template_part( 'template-parts/content/content-none' );
}

get_footer();