Know I'm chiming in late, but as an autistic writer, cover letters are a giant hurdle. Wiggle-room for interpretation for anything at all [reqs, themes, etc] means I will assume my submission will be unsuccessful even if it's a perfect fit. It'd be helpful if literary outfits of all flavors had standardized best practices [tech brain talking], or a LitSub Bible. Ambiguity is extremely hard to parse.