I think a lot of people are in the same boat and wish there was a nice ethical way to promote projects that worked without pushing them hard on people. I hope there is.
I wonder about ads for this. For example Reddit seems a decent place to advertise to target a group of people with a common interest, in a way that is not obnoxious. Do an hours freelance work for someone else and that’ll pay for a small test!
I tried it once, didn't get anywhere, and I'm too humble to keep doing it. Seems like you need to post it frequently--I look at the authors of front page Show HNs and they've posted it at least 5+ times.