You can disable UAC (thinking practical, not necessarily security minded - but for an auto login w/o password, what’s security?)

Popups: yes. But then you’d need to actively use other software besides steam. Why would you do that, if using only a controller? Also that can happen in Linux, too. If you mean those desktop notifications - those should be silenced automagically when running games.

For the logoff or shutdown: Set or createHKEY\_CURRENT\_USER\\Control Panel\\Desktop\\AutoEndTasks to 1 to auto kill hanging/not ending processes automagically. Also you can use WaitToKillAppTimeout there to define how long windows should wait before killing the processes (in milliseconds).

And regarding bitlocker after a bios update: why would you use bitlocker on such a machine (auto login on boot which would allow access to all files anyways)? Anyways, set or create HKEY\_LOCAL\_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\BitLocker\\PreventDeviceEncryption to 1 to prevent bitlocker from running after an upgrade. With Pro, you could also leverage GPOs for that.

At least for the new Steam Gamepad they announced trackpads to be able to control the mouse with the gamepad, so clicking away a popup or sich shouldn’t be a problem.