Same, that plus the persistent harassment. Personally, I'm skeptical that Duo in it's current format is designed to teach. The goal seems to be giving the impression you're learning so you but into micro transactions. I've seen people with multi year steaks who struggle with the target language and clearly would have been better served via another approach.

Maybe it's the course design, maybe the lack of supporting material, or some other weakness in the platform itself. But, I left out of frustration and started building Anki decks so I could have more control. As I'm now on my own, I've had to find supporting materials, which highlighted how poor Duo's explanations can be.

That last part comes down to the course design. Hopefully OP's platform doesn't force designing ineffective courses. This isn't my area of expertise, but I think it's important to recognize that adult learners can have different goals, even within something like learning a language (e.g. speaking, writing, accent, etc.)