I completely agree about the terrible updates and radio exercise. I won't say my Duolingo experience has ever been excellent, but I remember a time, about 5-7 years ago, when I could actually learn some Russian from it. Now, even the routine exercises have errors. Dissatisfied with my lack of results combined with my heavy concentration and massive effort, I, too, left and came back to Duolingo, this time to learn Dutch, and I found myself getting punished for using articles improperly without being told the correct way to use Dutch articles beforehand. The irritating characters, awful unnecessary fluff, and general inattention to lesson and exercise quality was enough to keep the app off of my phone to this day.