You can quickly turn the flashlight on (or off) by setting up a physical button shortcut. Follow these steps:
Go to the [Settings] App, and then select [Accessibility] >> [Gesture shortcuts] >> [Turn on flashlight] and enter. Then turn on the toggle [Double press the Power button].
Once enabled, simply double-press the Power button anytime to toggle the flashlight on or off.
Note:
Actual specifications may vary slightly between different models; please refer to the specific device in use. If you cannot find the exact path, try searching for "Flashlight" or "Gesture" in the Settings search bar.