I'm at a similar stage with my own product, so here's my answer to your question. Launch posts mostly reach other builders. The people who become users are usually in places where they're already asking about the problem, so answering those questions well, and mentioning the app only when it truly fits, tends to do more than an announcement. What I wish I'd known earlier is that family testers are kind. Watching them use it beats asking what they think. Pick the one task a new visitor should finish in the first few minutes, sit next to someone trying it, and stay quiet. Where they pause is usually the next thing to fix. Launch day as a starting line is spot on.