my phone says iPhone Unavailable.

If your iPhone has iOS 15.2 or later installed, check out this link→How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support. Otherwise:

See this Apple support link→If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

Or watch this companion video ⬇️

After restoring the phone using one of the methods above you can restore your most recent backup.

That usually happens after too many passcode attempts. At a certain point it may even lock out from any possible unlocking, where it can only be erased and restored to factory condition for iOS. There are some reports that it's happened due to "ghost touch" where the touchscreen is malfunctioning and registering phantom inputs.