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.
I had a similar experience, I was a heavy Duolingo user between 2014 and 2016 (I used it for Spanish) and I still believe that back then it was actually a pretty good way to learn the basics and I had learnt enough to be able to get by in Spain, have casual conversations with people, even hang out with a group of natives (but I also was a member of a few WhatsApp groups with Spanish people so I had a bit more practice).
Then they dumbed down the phone app and soon enough they did a similar thing with the website. Tips & Notes section was gone (or they kept it but removed a lot of information? can't remember), the tree-style courses were gone and replaced with some kind of a Path, the exercises became too easy and they'd make you translate from Spanish to English most of the time, which is much easier than the other way around. Then they removed the ability to type with your keyboard, added the "match the word pairs" exercise (which sucks if you use a keyboard and yes, I know you can try to use the numbers on your keyboard), all of which made the whole experience even worse and less effective.
I lost my streak somewhere in the middle of this enshittification process and I've never really gotten back to using the site, other than maybe checking once a year whether it's still shitty (and it always is).
In my opinion, back in 2014 Doulingo used to be a learning website with some gamification aspect that made the learning process a bit easier and more entertaining. Now it's just a gaming app which tries to give you a false sense of learning a language but in reality you aren't learning anything. Just a waste of time.
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