I've never had the pleasure of experiencing DuoLingo myself, but by all accounts it's an exceptionally time-inefficient way of learning a language. If the objective is to have fun playing a buzzy mobile game with the rest of the world then whatever, but if you actually want to make progress in a language you'd be much better advised to head over to something like Refold https://refold.la/ or Dreaming Spanish https://www.dreamingspanish.com/ . Even if you simply must have a phone app which does everything for you, you'd probably do better with something like Busuu https://www.busuu.com or Glossika https://ai.glossika.com/ .
So the AI furore is a bit ironic: people profess to hate "bullshit jobs", but if anything is a bullshit job it's probably providing the manpower for a language-learning app which doesn't actually teach languages effectively. Replacing mechanical-Turk slop with AI slop probably is a genuine productivity gain unleashed by AI here, yes? OTOH a drop in subscriber numbers and total user-hours is probably a good thing too, so don't let any of this put you off from giving up on DuoLingo.
The quality of advice on Reddit seems to be variable, unfortunately. Apparently https://www.reddit.com/r/LearnJapanese is full of people who've spent years doing Genki (https://genki3.japantimes.co.jp/en/ , probably an even bigger sinkhole for money, time and enthusiasm than DuoLingo) with little to show for it who are determined to drag everyone else into the same crab-bucket, for instance. OTOH https://www.reddit.com/r/latin/ used to be very helpful.
So the AI furore is a bit ironic: people profess to hate "bullshit jobs", but if anything is a bullshit job it's probably providing the manpower for a language-learning app which doesn't actually teach languages effectively. Replacing mechanical-Turk slop with AI slop probably is a genuine productivity gain unleashed by AI here, yes? OTOH a drop in subscriber numbers and total user-hours is probably a good thing too, so don't let any of this put you off from giving up on DuoLingo.