Background apps can crash at any time, causing the entire system to malfunction, with the delayed touchscreen response on your iPhone X as a symptom. You might try exiting all background programs to solve the problem. Apart from correcting problems, shutting background apps can also assist increase the battery life of your iPhone. Here's how you do it:

1. Swipe up from the bottom of the Home screen and then pause.
2. Touch and hold the app for a few seconds, then tap the minus (-) symbol in the upper-left corner of the app's preview.
3. Alternatively, as soon as you see the minus (-) indicator, swipe up to exit the app.
4. Reboot your iPhone Xafter closing all background apps and see if your iPhone X is already performing as expected.

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