iphone unavailable try again in 3 hours

You entered the wrong passcode several times. If you know the passcode try in 3 hours. If you don’t know the passcode:

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.