Use this snippet to sort Component Option Layered Filters by custom priority numbers.

woocommerce-composites-sort-component-option-filters.php

<?php
/**
 * Plugin Name: WooCommerce Composite Products - Sort Component Option Layered Filters by Priority
 * Plugin URI: https://woocommerce.com/products/composite-products/
 * Description: Provides the ability to sort Component Option Filters by custom priority numbers.
 * Version: 1.0
 * Author: SomewhereWarm
 * Author URI: https://somewherewarm.gr/
 * Developer: Manos Psychogyiopoulos
 *
 * Requires at least: 3.8
 * Tested up to: 5.3
 *
 * Copyright: © 2017-2020 SomewhereWarm SMPC ([email protected]).
 * License: GNU General Public License v3.0
 * License URI: http://www.gnu.org/licenses/gpl-3.0.html
 */

// To use this snippet, download this file into your plugins directory and activate it, or copy the code under this line into the functions.php file of your (child) theme.

add_action( 'woocommerce_composite_component_admin_config_filter_options', 'wc_cp_admin_filter_priorities', 10, 3 );
add_filter( 'woocommerce_composite_process_component_data', 'wc_cp_admin_process_filter_priorities', 10, 4 );
add_filter( 'woocommerce_composite_component_filters', 'wc_cp_sort_filters', 10, 3 );

function wc_cp_admin_filter_priorities( $id, $data, $product_id ) {

	$filters_priority = isset( $data[ 'filters_priority' ] ) ? $data[ 'filters_priority' ] : '';

	?>
	<div class="filters_sorting_priority">
		<div class="form-field">
			<label><?php echo __( 'Sort Filters', 'woocommerce-composite-sorting-options' ); ?>:</label>
			<input type="text" class="filters_sorting_priority" style="width:75%" name="bto_data[<?php echo $id; ?>][filters_priority]" value="<?php echo $filters_priority; ?>"/>
		</div>
	</div>
	<?php
}

function wc_cp_admin_process_filter_priorities( $component_data, $posted_component_data, $component_id, $composite_id ) {

	if ( isset( $posted_component_data[ 'filters_priority' ] ) ) {

		$custom_sort_order                    = implode( WC_DELIMITER, array_map( 'wc_clean', explode( WC_DELIMITER, $posted_component_data[ 'filters_priority' ] ) ) );
		$component_data[ 'filters_priority' ] = $custom_sort_order;
	}

	return $component_data;
}

function wc_cp_sort_filters( $filters, $component_id, $product ) {

	$component_data         = $product->get_component_data( $component_id );
	$custom_sort_order_data = isset( $component_data[ 'filters_priority' ] ) ? $component_data[ 'filters_priority' ] : '';

	if ( $custom_sort_order_data ) {

		$sorted_filters    = array();
		$unsorted_filters  = array();
		$custom_sort_order = array_map( 'wc_clean', explode( WC_DELIMITER, $custom_sort_order_data ) );

		foreach ( array_values( $filters ) as $loop => $data ) {

			if ( isset( $custom_sort_order[ $loop ] ) ) {
				$sorted_filters[ $custom_sort_order[ $loop ] ] = $data;
			} else {
				$unsorted_filters[] = $data;
			}
		}

		ksort( $sorted_filters );

		$sorted_filters = array_merge( $sorted_filters, $unsorted_filters );

		return $sorted_filters;
	}

	return $filters;
}