Posting too many times about your project may trigger some automatic and/or manual spam filters. https://news.ycombinator.com/newsfaq.html
Hit up your network and find someone who genuinely loves marketing a new product, and ask for help.
However... Also note that the startup market has changed a lot over the past couple of years. AI has made people shift from "how can I pay to fix my pain point?" to "How can I vibe code an app to fix my pain point?" Marketing in those conditions is much, much harder than it has been in the past.
When you actively participate in the community in good faith, you’ll generally get more feedback and engagement when you do want to showcase something you’ve created.