Some (but not most or all) of Duolingo's social and gamification features/social nags/upsells/"reminders" default on but can be turned off in the settings. But yes it's out of control and a strong reaason to disable Auto-update on the Duolingo app to not constantly the ever-more-AI-driven-nags/upsells. DL is becoming its own antipattern in the quest for revenue $$$ growth at all costs, e.g. reducing the actual amount of language being learned, beyond a certain plateau. I've been saying that here for a couple of years: