The problem here is that the rewrite rule uses an invalid regular expression. It’s important to run your rewrite rules through a rewrite rule testing plugin to check that it actually matches the URL you want to use. You don’t need to guess the result then refresh on the frontend to test that it works or not.
As for the regex itself, importantly none of the slashes are escaped.
I used https://regexkit.com/php-regex to test this with 123 as the ID, without escaping on the slashes the URLs did not match. A URL with trailing or starting slashes also did not match