My iPhone 14 pro max won’t turn on

Hello,

Make sure that it is charged:

Check the charging port for lint or other debris (use a bright light and a toothpick).

If your iPhone, iPad, or iPod touch won‘t charge

Then try this:

1. Press and quickly release the volume up button.
2. Press and quickly release the volume down button.
3. Press and hold the side button until you see the Apple logo (could be as long as 30 seconds) 

The timing is a little critical, you may have to try it several times. See this for more detail:

If your iPhone, iPad, or iPod touch won‘t turn on or is frozen

Good luck.