<?php
$all_tags = wp_get_post_tags (get_the_ID(), array('orderby' => 'name', 'order' => 'ASC', 'fields' => 'all'));
$output = "";
foreach ($all_tags as $tag) {
$tag_style = get_field( 'tag_color', "post_tag_$tag->term_id" );
$tag_link = get_tag_link($tag->term_id);
$tag_name = $tag->name;
$output .= '<a class="tag-button" href="' . $tag_link . '" style="background-color: ' . $tag_style . '">' . $tag_name . '</a>';
}
echo $output;
?>