I just found out how to set custom ambient mode timeout ("When to start" time of ambient mode).
- Just connect with WIFI debugging (enable Developer Mode and enable USB Debugging)
- and type `adb shell settings put system screen_off_timeout 60000` (60000ms = 1 minute, u can choose your own time)
- It's all :)
That is the command to modify the hibernate/sleep timer, the number equal to 1 hour in milliseconds, which can be modified to your preference.