I stumbled upon Mondly recently, which is great for learning a language and does a much better job at actually teaching and explaining than Duo does. It’s also cheaper, less gamified (but still fun) and eu-made!

I stopped at Duolingo because I got tired of them screwing about with and undoing user progress, gamifying things even more than before, and increasingly pushing for money/subscriptions.

Haven't found a good alternative yet. But Duolingo was driving me crazy.