J-10? Iran would be stupid to buy J-10.
J-31 or NOTHING from China.
SU-34 is waste of money, it’s a bomber and Iran isn’t sending bombers to Saudi Arabia or the Arabian ocean any time soon.
Iran needs air superiority fighters SU-30/35, MIG-31, etc.
While SU-57 or J-20 would be nice, realistically the only “5th” Gen fighter I can see Iran ever getting would be J-31 if China allows it for export (which it likely will).
However, Chinese-Iranian arms relations are almost as bad as Russian-Iranian.
So not hopeful for either as I said in past.