My Duolingo streak is 37 days and I just jumped on to do a lesson and retain my position on the leaderboard. I feel like the app itself is right on the cusp of being a valuable learning tool compared to being a silly game. I am okay with the idea of paying for “just okay” teaching if it helps me stay motivated and interested in the content. That may change in the future, I guess we’ll see!
What you're missing is that it's right on the cusp of being a learning tool instead of a silly game because it has regressed below the cusp. It was a useful learning tool, and its trajectory has been strictly downward for years now.
If it's working for you, don't let the negativity get you down! A year of daily Duolingo got me far enough along that I can now generally follow YouTube videos, news articles, and Reddit threads in the language I've been learning, with the occasional dip into Google Translate for unfamiliar words or phrases. The feeling of being able to just listen or read, and not have to consciously translate, felt like a door opening up in the world - a powerful motivation to keep working at it. Duolingo may not work for everyone, but in my experience there really has been value in it.
I found that with other study options, I learn faster and get tired less quickly (since they are less “puzzle-y” and more just language learning plain).