The best way to solve that is post some links and get the ball rolling. Can't get engagement without something to engage with. (I am guilty of not posting links myself lol)
Unfortunately, there's no real way of knowing. But for any community someone's gotta take that initial leap of faith and build it up from just a few people, even if it sounds like you're talking to yourself sometimes. At least until like-minded people start to show up and be drawn in to what you've built.
Even for the community that I'm trying to start up here, !presidents, it might just be my friend and I making posts, and it might stay that way for weeks, or possibly months. But that's a possibility you have to be okay with when starting up a community.
Try and talk to other individuals who are as passionate about your community's premise as you are. Friends you know irl, or people you've met in a similar community on Reddit. Having even just a few other people to engage with can make the process seem a lot less lonely and futile.