@charliekkk
So this is a super late response, but I felt like adding some more input. I am in archaeology (so tangentially related)but I felt that fit was the most crucial component. I applied to 2 schools and got in to 1, approaching it as an exploratory year hoping for an acceptance. I got in touch with 3-4 professors from various schools a year before applying and gave them a run down of my interests, background, and current work. I took two years off to work after undergrad and wanted to make sure that the fact I had taken time to consider my specific interests and fit was noted. My undergraduate advisor recommended taking some time before returning to graduate school and I think it was good advice.
A common theme in the feedback I received from early communication was about my background, which is rather interdisciplinary consisting of lived practical experience and a broad liberal arts education. They seemed very interested in my specific background experience, but I think that is more a result of my subfield of interests. Further, a lot of the professors referenced each other as potential PIs/schools to consider and it gave me some insight into the relationships within the field. I felt confident when applying to the school I was accepted by of my fit with faculty, and the program at large.
Regarding writing samples, I provided two writing samples, one was an upper level undergraduate paper and the other a modified undergraduate honors thesis. They clearly showed my writing style, analytical ability, and illustrated my interest in combining lines of thought (even if they didn't address the themes I am hoping to pursue in the PhD). In my SOP I also discussed some of my interdisciplinary interests, but it was more straightforward regarding potential research and highlighted my fit with the department. I felt confident doing so because I had been in touch with potential PIs and they knew of my interests, and I wanted to make sure I was presenting myself accurately. I did not want to submit something that is not representative of my interests, or theories I'd not be willing to work on for 5+ years. I think the SOP in conjunction with my resume provided a good picture of what I have done and what I want to do, really complimenting each other.
Hope this is helpful, and lmk if you have any questions!