I'm not. I'm a new user, and I notice that Duolingo kind of sucks, but I am getting some amount of value out of it. I'm very open to suggestions for better language learning apps, though.
When you hit diminishing returns on a walled-garden language-learning app, it's time to create a continuous intake of real-world media at your level that you enjoy, plus a suite of inline understanding+memory tools to extract the maximum learning out of that media.
I have been following many of the recommendations on https://learnjapanese.moe/resources/. Most of them are language-specific, but perhaps you can still draw some inspiration from the methods and look for equivalent tools in your target language.