My coworker and me are already starting to feel the pain on various core APIs, the latest being notifications, which according to my coworker had 3 full revision, and finding documentation for the last one is hard. Storage (with Android 11 modifications) is another place where the documentation is starting to get stale. Those are not the only APIs were the documentation was poor.
In my opinion, Android documentation is at the same place iOS documentation was about 5 years ago (before they started removing entire pages from the documentation) : overall very good, but a few places were it's not up-to-par or downright horrible. I don't expect the quality to improve in the future.