The ONLY way to truly unlock a iphone is to ring network provider and ask them to eamil apple and send the user network code takes 2-6 days and then whatever sim is inserted will work.
Ive tried tge teatherd and non teatherd jailbreaks the cards that you insert into the sim holder to “bypass” the lock and all of them end up “no service”
I rang ee up for the wife to unlock her 4s after she had paid her contract out. The reply was a 15quid charge to send the code I argued to the hilt about how she “owned” the phone and they simply stated read our terms and conditions its our legal policy. So ended up stumping up the cash.