Just a quick heads up, in a thread the other day I was told by dang that newsletters aren't applicable for Show HN as per this page I'd never noticed before: https://news.ycombinator.com/showhn.html So take my upvote but at the same time, I imagine this post might be removed in some form later(?)
You may find it useful to submit it to these various directories as well: https://newslettercrew.com/list-of-newsletter-directories/ .. plus places like /r/erlang, perhaps. It would probably work out better for HN if you have some blog posts or articles and promote the newsletter off the back of them :-)