Easy way to find laptop schematics is by OEM name. In this case, Wistron LOS-1. It's sad that these "researchers" couldn't find it for free.[1]

further denying funds to the DDoS SaaS or botnet rental they'd eventually have spend it on.

That is unfounded fearmongering. I suspect at least some of the funds go to paying neighbourly employees working at said OEMs so they'll share more schematics. Most if not all the schematics you see available are leaks, after all.

[1] Maybe if they do come across companies leaking them, they'll be do-gooding and closing those "holes" (and effectively fighting against right-to-repair), so perhaps it's better that they didn't.