Starlink or any other sort of satellite internet, but these are relatively easy to jam and detect. There are ways to minimize that but obviously not available to civilians.

The issue is, if you control the Network DMZ, it's extremely difficult to bypass. In Xinjiang and Tibet (which has a similar setup) they used to use smuggled Kazakh, Nepali, and Indian SIM cards but that was cracked down.

A lot of the info from inside Iran that is not regime connected is coming from areas in Iranian Kurdistan where an Iraqi SIM could be smuggled or accessed somewhat easier than other areas.