How the heck do people get 100s of subscribers on the product waitlist? - Please, don't share the success stories, tell me failures!

Hi,
2 weeks back I announced that I am building a directory of homeschooling resources . I wanted to validate my idea before actually starting to code but I only got 10-12 subscribers interested in the product.

I believe that Is because I am unable to reach out to my audience.

My audience is homeschoolers and they mostly hang out in Facebook groups, Reddit, or WhatsApp groups. And most of these groups do not allow posting about the product or any self-promotional content. I feel helpless.

I am slowly trying to get into the communities but it is a long road.

Now, from where do I get people to join the waitlist?
I am going to build this product anyway because this is something I need and I spoke to a couple of homeschoolers who validate this idea.

Is this the same for everyone out there? Do we all feel this kind of frustration and confusion in the beginning? Those $0 to $10,000 MRR and 1200 subscribers in 1-week posts are so deceiving.

For the past few days, I am feeling stuck and recording it here on Indie Hackers so when I become rich I don't forget this phase of my journey while writing my overnight success story.

Thanks!