On main branch 3.5 you cannot connect joycons unlike stable. It's inconsistent but when you connect every so often it crashes steamOS and restarts.
select the properties of the eXtreme (or other USB) controllers, and toggle the setting that allows you to disable the USB ports to save power when not in use. Even some desktops have this on by default.
When this mode is in operation (i.e. the stick is not at rest), all other mouse movements are ignored. When using the MOUSE_AREA stick mode, the stick value directly sets the mouse position. So moving the stick rightward gradually all the way to the edge will move the cursor at the...