Iphone XS MAX has become irresponsive

See this support guide:--> Get help with the display on your iPhone, iPad, or iPod touch - Apple Support

If you get no improvements, since your device is still covered by warranty, I'd have it inspected at an Apple Store or Authoized Service Provider:--> Apple – Location Selector

Regards

Giulio

This has been happening to me a lot recently, as well. Try restarting the phone by restarting it (Volume up or down + power at the same time).

There could be many reasons for why it is not working as it should, but there may not be "one" cause that is the same for everyone. Contact the support team or make an appointment in store so the issue can be resolved and looked at more.

If you don't have anything (cover/screen protector) that can obstruct or interfere with your "touch screen", if you already tried a forced restart of your unit and if you followed (to no avail) all the steps provided in the support guide I posted, it could be a hardware failure. But we can't diagnose that issue remotely, sorry.

Regards

Giulio