there's a giant banner saying that screen recording is on, while there's nothing for recall? im not sure im following your question.

There are many screen recorders that do not show a "giant banner", and even if there weren't, it's ~200 LoC to implement an efficient screen recorder for Windows that's hidden.

You can install any app to do anything on Windows. The issue here is that this is built-in, so it will be everywhere, all the time.