I have an author loop with a profile picture that saves into ACF custom fields and I want to use it as get_avatar but it returns blank.
Here is a snippet:

$get_avatar = get_user_meta($user->ID, "wp_user_avatar");
$avtar = add_filter( 'get_avatar', wp_get_attachment_image($get_avatar[0], 'thumbnail') , 10, 3 );

Now,

<div class="profile-photo"><?php echo get_avatar($user, 100); ?></div>

it shows blank div