Kindles, Kobos, and KoReader

I jailbroke my old Kindle Oasis a while back, and while I mostly kept using my Kindle Paperwhite, the limitations of the Kindle interface started to chafe. I have pretty crappy eyesight, and at night, in the dark, if I look up a word in the dictionary, I can barely read the font. The stock option allows changing to a larger font, but that is EVERYWHERE, and causes the Wikipedia lookup to cut off…