I want to write technical posts professionally, but don't know where to start

I want to write like Julia Evans. Short, informative technical posts, explaining complex topics, or exploring new technologies, or telling the story of a technical journey, which in simpler words is telling people what problems came during the course of work and how they were solved.

I told my manager about the situation, since he's suddenly started getting on my back about the importance of communication, and he told me to start with the topics I want to write on. But...like, I don't know what topics I want to write on. How do I even get to the place where it's easy to identify topics to write on? That's an interesting, challenging problem in itself, and the problem domain I work at professionally is specific and small enough that I can't generate enough topics for the larger reader populace.

So I'm lost, confused, frustrated about my inability to get into better technical writing, and not becoming a good technical writer. A thought leader, a thinkfluencer, I don't want to become those necessarily, but I do want to be known as somebody known for their good technical communication skills and their writing. The ideal situation would be if I was hired for new positions based on my writing abilities.