Map Facet – change MarkerClusterer text color

<?php

// Add to your (child) theme's functions.php

add_filter( 'facetwp_map_init_args', function( $settings ) {
    for ( $i = 1; $i <= 5; $i++ ) {
        $settings['config']['cluster']['styles'][] = [
            'url' => FACETWP_MAP_URL . '/assets/img/m' . $i . '.png',
            'width' => 53,
            'height' => 53,
            'textColor' => '#fff'
        ];
    }

    return $settings;
});