Newer iOS versions (15.8.x, 16.x) broke many legacy loaders. If the tool doesn't support your current version, you must put the iPhone 7 into DFU mode and flash a compatible version (like iOS 15.6) using iTunes before using Unlocktool.
Are you trying to perform a or a Passcode/Disabled bypass ?
Follow these consecutive troubleshooting steps to provide the software with the right files and fix the connection loop. 1. Manually Download and Place the Ramdisk File