I am successfully running videokiosk on lenovo p11 plus tablet with Android 11 BUT the audio volume level is adjusted (reduced) by the system after a number of hours of play to a loudness level that is too low to hear. Can this be overridden so that there is consistent sufficient audio volume, and how do I do that?
This is a vendor feature of your Android device. There are two possible options (1) return this device and get one that does not have this feature, (2) look in the system setting to see if you can turn the feature off.
Here is an article with more information regarding auto volume control: