Update per Carsten's suggestion.

includes/core/classes/class-setup.php

@@ -183,14 +183,17 @@ public function filter_plugin_action_links( array $actions ): array {
 	 * @return void
 	 */
 	public function activate_gatherpress_plugin( bool $network_wide ): void {
-		global $wpdb;
-
 		if ( is_multisite() && $network_wide ) {
-			// Get all blogs in the network and activate plugin on each one.
-			$blog_ids = $wpdb->get_col( $wpdb->prepare( 'SELECT blog_id FROM %i', $wpdb->blogs ) ); // phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.UnsupportedIdentifierPlaceholder, WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
+			// Get all sites in the network and activate plugin on each one.
+			$site_ids = get_sites(
+				array(
+					'fields'     => 'ids',
+					'network_id' => get_current_site()->id,
+				)
+			);
 
-			foreach ( $blog_ids as $blog_id ) {
-				switch_to_blog( $blog_id );
+			foreach ( $site_ids as $site_id ) {
+				switch_to_blog( $site_id );
 				$this->create_tables();
 				restore_current_blog();
 			}