How to get past a forgotten iPhone passcode?
Connect the device to a Mac over USB and restore it using Finder. Since you have control of the AppleID that locks that device, you only need to get it connected to a network again. You can also see the last backup date online and know how much data might be lost in a restore.

Once the restore process is complete, you can restore the backup or just set up the phone as new. The apps, data, passcode will all be erased.