Hello Sher413,
We understand that you're not able to power on your iPhone and 11 pro Max. We'd like to provide you with a few steps that may be assist you:
If your iPhone won't turn on or is frozen
"If your iPhone has a frozen screen, doesn't respond when you touch it, or becomes stuck when you turn it on, learn what to do.
If your screen is black or frozen
Follow the steps for your device.
On your iPhone 8 or later, including iPhone SE (2nd and 3rd generation)
- Press and quickly release the volume up button.
- Press and quickly release the volume down button.
- Press and hold the side button until you see the Apple logo.

4. If your phone doesn't turn on, follow these steps to check your hardware and charge your phone. You might need to charge for up to an hour."
If you're still unable to power on your phone, we suggest that you have your device evaluated by a certified Apple technician. You can follow this link to connect with them : iPhone Repair & Service
All the best.