You can try to add a filter that will select a default value if none is selected already. Perhaps something like this:
add_filter('acf/load_value/name=your_taxonomy_field_name', 'set_default_taxonomy_selection', 10, 3);
function set_default_taxonomy_selection($value, $post_id, $field) {
// Check if the field has a value
if (!$value && empty($_GET['post'])) {
// Set the default term ID here
$default_term_id = 7;
$value = $default_term_id;
}
return $value;
}
