I found this semester that my best poems came from ideas or experiences rooted in the most emotions. As a third culture kid, I often found myself writing about being home, finding someplace to “rest my bones” (as much of a cliche that is), and themes such as those.
On an almost unrelated note, I found that these pieces, talking about how hard living abroad or feeling alienated in a place I no longer had roots to (New Delhi, as my friends no longer lived there and I had graduated high school) had an extremely narrow audience, or could only be understood with a brief lecture or by somebody who had an extensive knowledge of my very non-typical background.
By writing poems that narrowed down on universal emotions such as loss but with a specific enough narrative that drew from my experiences as a third culture kid (TCK), I found my writing became raw yet unique, something I was trying to achieve in the first place.
So yes, writers will write what they know. But keep in mind your audience and what Nate Pritts said during his visit, that people are “hardwired, narrative, chronological beings”. I believe that we all have a story to tell, something unique yet, (please forgive me for this next word), relatable.
I agree that people tend to write what they know. I think it can produce some of the most emotional work. I also think you’re experience as a Third Culture Kid is important for your development as a writer, and even if it isn’t necessarily “relatable” to everyone, you should try to flesh it out. Your poems are yours before they go out into the world.