Iterating through Object Array to customise display of full custom taxonomy for custom post type

Instead of echoing right away, save the category names into an array, and then you can implode the array, which means output it with whatever separators between items you wish:

<?php
if(get_the_terms($post->ID, 'kernal_category', true)) {
        // Create an empty array
        $categories = [];
        $kernal_category = get_the_terms($post->ID, 'kernal_category', true);
        // Save each category to the array
        foreach ($kernal_category as $category) {
              $categories[] = $category->name;
        }
        // Now output with implode
        echo implode(' > ', $categories);
}
?>

That way the spaces and caret separator will go between the items, but not after the last item.