I contacted Nothing support. they said "The regional lock for Nothing phones usually only affects the zone where a phone intended for a region can be activated for the first time with a SIM card. This is to prevent re-exporting and selling the device in different areas than the ones it was originally assigned for sale by Nothing.
Once the network lock is successfully removed, the phone can then be used with SIM cards from other regions. However, it is important to note that if the phone is restored to factory settings, the lock will be reactivated. In such case, the phone will need to go through the same process that you need to request a SIM unlock to use."
