These changes require to install a Divi child theme with a Blog module inside. Check the following article if you don't have a child theme with the Blog module in it yet:
Moving the blog module in child theme article
Next, open up includes/Blog.php file from the child theme folder and search for this code:
echo '<div class="post-content">';
Note: You can find this specific line on 2 places on the same file.
You should edit the 2nd part mostly around line no. 1559 as shown on the screenshot below:
Add your custom fields code just below it like this:
$my_key1 = get_post_meta($post->ID, 'my_key1', true) ? get_post_meta($post->ID, 'my_key1', true) : "";
if($my_key1 != "") {
echo '<div class="mykey1">'. $my_key1 . '</div>';
}
Add more meta keys from your custom fields and custom CSS class to customize it as required :)