How do I gain access to my iPhone XR displaying iPhone Unavailable?

Hello,

It appears you may have a disabled mobile device or forgotten device passcode. Refer to this support article for various methods that you can use to resolve this. Which one you can use depends upon your equipment configuration. --> If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support

If you forgot the passcode on your iPhone, or your iPhone is disabled or unavailable -

Click on the link for instructions on how to reset your passcode without a computer if you have iOS 15.2 or higher.

How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support

Click on the link for instructions on how to reset your passcode using a computer.

If you forgot your iPhone passcode - Apple Support