Doesn't GSM require mutual authentication via ki that's stored on the sim card and only known to the operator? Getting stingrays to work is easy mode because all it has to do is relay the traffic while capturing the IMEI/IMSI in the process, but if you want to act as a real cell tower that's much harder.
https://en.wikipedia.org/wiki/SIM_card#Authentication_key_(K...
I don’t know how many people in Iran have devices with eSIM support but with that you could probably do it. You would need internet access once to activate it but after that you could use the mobile network (and also provide a WiFi hotspot to other people to activate the eSIM).
You could airdrop simms to seed the process