Your code only creates the checkbox, you need also to save the value like that
add_filter("product_type_options", function ($product_type_options) {
$product_type_options["wildcard"] = [
"id" => "_wildcard",
"wrapper_class" => "show_if_simple",
"label" => "Wildcard",
"description" => "Description",
"default" => "no",
];
return $product_type_options;
});
add_action("save_post_product", function ($post_ID, $product, $update) {
update_post_meta(
$product->ID
, "_wildcard"
, isset($_POST["_wildcard"]) ? "yes" : "no"
);
}, 10, 3);