There are a lot of variables to this question so bear with me as I give you a solution that will get you close.
assuming the field is called myimage and you’re returning the image url in the field control…
open your home.php file in your child them (if you don’t have a child theme, make one and copy the home.php from the main theme. Then in the home.php that is in your child theme put this code:
<?php if( get_field('myfield') ): ?>
<img src="https://wordpress.stackexchange.com/questions/267883/<?php the_field("myfield'); ?>" />
<?php endif; ?>
where ever you want it to appear on the homepage.
If you want the hero to be in the header you may need to use the header.php and use this code.
<?php
if ( is_home() ) {
// This is the blog posts index
if( get_field('myfield') ): ?>
<img src="https://wordpress.stackexchange.com/questions/267883/<?php the_field("myfield'); ?>" />
<?php endif;
} else {
// This is not the blog posts index
}
?>