Thanks! That's a well-written paper. I don't know why I keep falling for science journalism's simplified explanations.
I've so-far only skimmed it, but to answer my question they find light dark matter to be the simplest case (I didn't see a specific range, but they used 250keV as an example), but they also considered a scenario where "dark-zillas" (mass >> 10^10 GeV) are plausible. At least that still narrows the search space a bit 😅
In two languages I'm learning, German and Chinese, I've found it to suffer from "translationese". It's grammatically correct, but the sentence structure and word choice feel like the answer was first written in English then translated.
No single sentence is wrong, but overall it sounds unnatural and has none of the "flavor" of the language. That also makes it bad for learning - it avoids a lot of sentence patterns you'll see/hear in day to day life.