What’s funnier is that both my son and my wife have the Paperwhite 10th generation, but only my wife’s device has dark mode. Same exact device, different software depending on when it was bought.
The second major reason for Jailbreaking is that KOReader can do DRM through a plugin so I was finally able to loan out ebooks from my library. No need for a new device, the 10 year old one works extremely well with the right software