Need help breaking honto.jp's DRM - sh.itjust.works

I purchased an ebook (two of them, actually) from some Japanese site called honto, but of course, stupid old me didn’t realise that Digital Restrictions Management was going to make my life a living hell. Has anyone had any luck with cracking them, or did I just spend 730 Yen on a nothingburger? Link [https://sh.itjust.works/pictrs/image/dc0e965d-5ccb-4020-94c0-67dc8cdb3ef8.webp] Apparently, there are some local files on my phone from “doenloading” the ebook, but they won’t load. In the browser I had a little more luck, but the images are scrambled when I attempt to “inspect element”. What do I do? I really want to get this to work…