Iran has this clause that they can technically allow someone to renounce their citizenship: the Council of Ministers has to accept your request and they simply never will, so you have to stay.
I have a friend in Iran that is a born Iranian who wanted to renounce his citizenship for years. First he was told it’s impossible before having completed the mandatory military service (a lie, it is not a requirement by their own laws). He finally caved in and did the 2 years bullshit service. Then, they told him he needed to be 26. Ok, fine, he waited until then. Then they told him his questionnaire form was outdated and he needs to apply again with the new one. How to get the new one? Only way seems to be over the official page that links to a dead link, literally 404.