Tech blogs are the standard way tech companies advertise to engineers. You must understand a tech blog is not meant for you to "tell" tech blogs exist for you to "show."
If you think of your blog as an advertisement with technical info you will fail. If you think of your blog as a public display of technologies and processes that people might find useful or relevant to their work, it can succeed.
After tech blogs, getting other people to mention you or display artifacts related to your company seems valuable.
Showing up at things like DefCon or other conferences and interacting with people in good faith seems productive.
I think the engineer crowd is a crowd that will smell bullshit and recoil, but if you're not a pest and show (not tell) that you can reduce workload, I think all of us would like less problems to think about.
This can clearly be seen as a covert ad - I'm not complaining, but if you were not doing it on purpose then consider doing so.
I find write-ups in technical articles/blogs by people who use stuff and find it valuable and can articulate why to be salient.
Do you have a wide enough group of users with such output that you could suggest such write-ups from without twisting their arms too hard? The border with edvatorial is grey, but it's worth considering.
Sponsor tutorials to win over those in learning mode. They are the group who is open to change and willing to try/learn about new products.
For the busy experienced developer try solving a problem using your tool and spread on hn, twitter, discord, github, reddit.
The problem you have is the market has caught up to you. To continue to do well you need to become a marketing company instead of a pure leading edge tech company
Put this (or something like this) in your About section of your HN handle:
CEO of userify.com (innovative SSH key management, self-hosted and saas)
Then participate regularly.
A recent article explained how to effectively use information marketing to reach the HN audience (and beyond).
How to hack Hacker News (and consistently hit the front page): https://hw.leftium.com/#/item/35912649
How do you advertise to the very smart and technical users when they run ad blockers?
In my opinion your site would need a really good technical write-up on a blog section that walks through how your application solves problems people have been handling manually so that it creates it's own compelling reasons even without having to describe the reasons in sales speak. In other words if the technical people here read your technical write-up they should already have ideas in their heads about how it solves management, audit, compliance and other facets of ssh private key management and public key trusts/identity mapping making their lives easier and freeing up time for them and their management teams.
There should be a way to try out your application and ideally a step-by-step instruction for how to self host it. To increase adoption provide people with Ansible, Chef, Docker, Cloud init and other pre-baked scripts so they can just about drop it into an environment with minimal configuration, fire up the required servers and tie everything into it.