You are using a checkbox, this allows multiple values to be selected so the field will return an array. You’re also returning the Term ID, so you need to get the term. If you return term objects you can do
$categories = get_sub_field('kategorie');
foreach ($categories as $category) {
echo $category->name.' ';
}
as it is you need to do
$categories = get_sub_field('kategorie');
foreach ($categories as $category) {
$taxonomy = 'category';
$term = get_term_by('id', $category, $taxonom);
echo $term->name.' ';
}
