functions.php

<?php

function elodin_section_block_get_the_colors_formatted_for_acf_from_theme_support() {
    	
	// get the colors
    $color_palette = current( (array) get_theme_support( 'editor-color-palette' ) );

	// bail if there aren't any colors found
	if ( !$color_palette )
		return;

	// output begins
	ob_start();

	// output the names in a string for use in Iris
	echo '[';
		foreach ( $color_palette as $color ) {
			echo "'" . $color['color'] . "', ";
		}
	echo ']';
    
    return ob_get_clean();

}

function elodin_section_block_get_the_colors_formatted_for_acf_from_theme_json() {
    
    ob_start();
    
    // get the palette from the theme defaults, as defined in theme.json
    $color_palette = [];
    if ( class_exists( 'WP_Theme_JSON_Resolver' ) ) {
        $settings = WP_Theme_JSON_Resolver::get_theme_data()->get_settings();
        if ( isset( $settings['color']['palette']['theme'] ) ) {
            $color_palette = $settings['color']['palette']['theme'];
        }
    }
        
    // output the names in a string for use in Iris
    echo '[';
		foreach ( $color_palette as $color ) {
			echo "'" . $color['color'] . "', ";
		}
	echo ']';
    
    return ob_get_clean();
}

add_action( 'acf/input/admin_footer', 'elodin_section_block_register_acf_color_palette' );
function elodin_section_block_register_acf_color_palette() {
    
    $color_palette_json = elodin_section_block_get_the_colors_formatted_for_acf_from_theme_json();
    $color_palette_theme_support = elodin_section_block_get_the_colors_formatted_for_acf_from_theme_support();
    
    //* use theme.json values first, then fall back to add_editor_support colors if not. Bail if there aren't any.
    if ( $color_palette_json !== null ) {
        $color_palette = $color_palette_json;
    } elseif ( $color_palette_theme_support !== null ) {
        $color_palette = $color_palette_theme_support;
    } else {
        return;
    }
    
    ?>
    <script type="text/javascript">
        (function( $ ) {
            acf.add_filter( 'color_picker_args', function( args, $field ){

                // add the hexadecimal codes here for the colors you want to appear as swatches
                args.palettes = <?php echo $color_palette; ?>

                // return colors
                return args;

            });
        })(jQuery);
    </script>
    <?php

}