I've previously pondered how we would have approached our early steps if we were completely unknown, and the best option i can think of is a kind of sincere, influencer marketing approach.
i.e. if you dont have the voice in the industry that people will listen to, find people who do, and get them to see your product. Most industry leaders are constantly looking to up their game, so you should be able to catch their eye, and if your product is awesome, they will say so
I think it would depend on how those experts roll.
For infosec for example, i think if your product did "X amazing thing", then you'd definitely get a seasoned experts attention if you tweeted "hey, we built a thing that does X amazing thing, give me 5 minutes and i'll show it to you"
I think theres a part of this that means your products has to convince them in the 5 minutes they give you (or at least has to convince them to give you 5 minutes more)
i.e. if you dont have the voice in the industry that people will listen to, find people who do, and get them to see your product. Most industry leaders are constantly looking to up their game, so you should be able to catch their eye, and if your product is awesome, they will say so