My iPhone says iPhone unavailable

This message appears because the wrong passcode was entered too many times. The iPhone must now be reset / erased and then set up again.

If your iPhone is running iOS 15.2 or higher........(it appears that it might be).......you can use the instructions linked just below which will not require the use of a Mac or PC:

How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support

If you are not sure which operating system is installed on your iPhone, please use the link below, which will require the use of a Mac or PC.

If you forgot your iPhone passcode - Apple Support

If you have a backup of the phone, you can use the backup to restore the data on the phone during the new setup.