The project is ready for evaluation by the Internet community, but not yet production use. It needs open source contributors and constructive critique.
I've been working on it solo for >2y, and have circulated a handful of releases to a few friends.
It hasn't yet been publicly announced. How can I publicize this?
Write a blog post, short, with the key things that will make it evergreen. Use good keywords in the title.
Then don’t worry to much about a big launch, just share it on the socials you use. Over preparing can just set you up for disappointment.
For example, how does your software compare, from a user’s perspective, to existing alternatives? What parts of it exist today, and how much work remains? Are you credibly in a position to deliver?
Your announcement needs to communicate your progress, competence, and realistic plans, or readers will tend to assume your project, like many, is so much vaporware.
Just create a show HN and we'll judge. :-)