At the time of writing, iPadOS 26.7.1 is current. Updating to this most recent version may help. For your iPad Pro M4, you also have the option of upgrading to iPadOS 27.0.1.
The iPad User Guide may help with setting-up FaceID:
Set up Face ID on iPad - Apple Support
Have you installed a screen protector on your iPad? If yes, consider removing the it - as some poor quality screen protectors can interfere with the FaceID sensor array.
If your iPad is not operating as expected after performing a forced-restart, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:
How to back up your iPhone, iPad, and iPod touch - Apple Support
When you are happy to proceed, you can perform the reset from iPad settings:
Settings > General > Transfer or Reset iPad > Reset > Reset All Settings
If the problem still doesn’t clear, the next step is to reset the iPad to factory settings:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Otherwise, 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 and perhaps easier, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, 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 hands-on test and assess your iPad - and you can explore your available options:
Genius Bar Reservation and Apple Support Options - Apple
User level: Level 1 (4 points)
