yeah learning to read kuzushiji takes a lot of time and effort, even just for hiragana (kanji is on a completely other level!). i think it would be very hard to learn without a teacher, but maybe tackling a text that you are already kind of familiar with and comparing your reading with the output from the miwo app might work (miwo isn't perfect but it is pretty darn good)

yeah, i don't know so much about the history, but there seem to have been a few attempts to make joined-up moveable type in Japanese (even one type foundry in the Meiji period made a hiragana font that had pseudo-joined-up glyphs: one set with a connecting line below, one set with connecting lines above and below, and one set with connecting lines above). it sounds like a nightmare to produce, organize, and arrange kuzushiji ligatures!