iPhone disabled. Connect to iTunes. No backup
I would connect this to any iTunes you have that has ever had a chance to save an unlock key for that device. Unless you already have a trust relationship between iTunes in a computer and this phone, it’s going to wait for you to decide to erase it or you find a way to jailbreak it or crack the protection.
If you have full trust, it will reverse the disable when it’s connected to the internet and your phone is connected and everything is working. Update should prompt to make a backup, allow it. Restore likely will not do a backup, but I don’t have a disabled device to test this for you.