[teutocat]

The very helpful support from ereader.store showed me a very good way to mitigate the problem.
The "Any Screen Timeout Plus" app can manage timeout settings that the Boox Tab X cannot handle.
If the developers of the "Any Screen Timeout Plus" app found a way to suspend sleep, then it should work in MobileSheets, right?
Now I'm finally able to practice a song for a long time without the tab switching off. With the Tab X,
this is particularly uncomfortable because the button to turn it on is very difficult to operate