In my experience it really depends on the studio you are in.
Like you I was a 3D Environment artist and wanted to transition to technical artist.
When I got hired as a 3D artist the company didnt need a tech artist, it needed assets. As time went on they eventually found the need for one. some studios dont.
For me technical art is all about solving problems, if you can solve problems for other people at the core, thats what technical art is.
This includes anything from
- automating packing of channels in substance
- making a python environment to automate some startup functionality for n number of programmes.
Once it saves someone time or pushes the boundary of something.
I also find that curiosity has served me very well. When i get curious i put my head in the rabbit hole to try and solve the problem, once the problem is solved il come back out of the rabbit hole until I have time to investigate more. Once I get time, il jump head first into the hole never to be seen again.
The take away is that you should do what you find is most interesting/ engaging. Take small bites of things your working on and build those up to be something bigger.
Its less about a specific skill and more about the skill to learn and grow. Nobody really truly knows a topic/subject. The difference between the people who seem like they do is that they are not afraid of it or to learn it. It will take time, and thats okay.