Samsung Galaxy Note9 - Factory Data Reset (Powered Off)
A factory data reset may help with a blank or frozen screen, apps crashing or freezing, keypad/touchscreen problems, can't hear, device making noises, can't make or receive calls, and device won't sync.
For devices with Android Device Protection turned on, it's imperative Google™ sign-in credentials are known prior to completing a factory reset with the device powered off. If credentials are unknown, do one of the following:
Attempt to sign in with any Google account previously used on the device.