It should work the same, you just need to change the hook it runs on
// img unautop
function img_unautop($pee) {
$pee = preg_replace('/<p>\\s*?(<a .*?><img.*?><\\/a>|<img.*?>)?\\s*<\\/p>/s', '<div class="figure">$1</div>', $pee);
return $pee;
}
add_filter( 'acf_the_content', 'img_unautop', 30 );