One common question for software developers is how to progress from "intermediate" to "senior"—whatever those titles mean. A lot of the journey is how you position yourself and stay confident, but in terms of taking these leaps in your own capacity as a technologist, I have a thought on the subject.
My biggest leaps on my "main competency" have been when I have taken opportunities to learn a different one. My "main competency" is as a Rails developer, and while I feel comfortable transitioning technologies, this environment remains my bread and butter. But my leaps and gains have always been when I have learned something different altogether.
Knowing how Go handles a use case gives me a lot of context into why and how Ruby does it. Depth and breadth are not at odds in this sense. Learning a new and different thing will increase depth. This has always been my experience. I don't necessarily want to use a bunch of different technologies. It would make my head spin. But as a matter of developing my career, this has been a useful pattern.
Functional programming helps you better understand OOP. Type systems help you understand typeless. Schemaless helps you understand schemas. And on and on and on.
Consider learning new things as an exercise in perspective. Whether or not you're captivated by the new thing, the exploit will have been worth it.