Frozen iPad not responding to force restart

If you do a forced restart correctly it will always work unless the hardware has failed:

If your iPad won't turn on or is frozen - Apple Support

The first two presses must be short and quick, the 3rd button must be held until an Apple logo appears, which can take up to 30 seconds. Ignore “Slide to power off” and keep holding.

If your iPad is not operating as expected, connect the iPad to its Power Adapter and allow the iPad to charge. While still connected to the Power Adapter, perform the forced-restart:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button; do not release button when you see the power-off slider.
4. When the Apple logo appears, which it will, release the top button.

When performed correctly, the iPad will restart.

If the problem persists after performing the restart, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad - and you can explore your available options:

Genius Bar Reservation and Apple Support Options - Apple

You're very welcome.