@ajb2k3 I think thats not true. There is no ino files or basically anything what refers that it is done with arduino ide. And by my understanding it is not even compatible with any level witth it.
I do not have an M5AtomS3 Lite. But I tried the button example with an M5AtomS3 (which uses the same GPIO41 for the button) and it works for me. Care to share the code you tried where BtnA did not work?