I used Duolingo a fair bit in 2015–2017 to improve my Swedish, and generally enjoyed myself. Having not touched it for most of a decade, I downloaded it earlier this year to try my hand at basic Greek and wow but it’s gone downhill. Everything is massively over the top, all subtlety has left the system, and when I stopped after a couple of days because I couldn’t deal with the intensity they sent me nagging messages for over two weeks in more and more pleading tones trying to get me to come back. I’d never use them again at this point.
Edit: just went to delete my account and they’ve got a tearful owl above the “Erase personal data” button to try to guilt-trip me into staying. https://drive-thru.duolingo.com/static/owls/sad.svg