To be honest, I’d love to know the answer to your question, but I’m not quite sure what to tell you.
In total, I’ve seen four or five streamers playing my game, and I haven’t the faintest idea how they discovered it...
On the other hand, I’ve contacted several content creators but haven’t received a reply, so I suppose it all comes down to how your game looks, whether it looks interesting, and pure chance that the right person stumbles across it...