This war have proved that Iran can put offensive, but it lack defensive. Now there are two sides to defensive forces.
1. Land based.
2. Air based.
I think it is right time for iran to start investing in air based defensive weapons. I am talking about airforce. A modern air force provides:
1. Air defense interception
2. Combat air patrols
3. Escort for strike aircraft
4. Suppression of enemy aircraft
5. Better battlefield awareness through airborne sensors
Pakistan can help in that regard by gifting some 8-10 older JF-17s to iran to train their pilots and get them ready for newer JF-17 Block 3. It wont cost much, but it will give you the capability to go behind israeli fighter jets or atleast put some resistance to them in the air.
Even if they cannot defeat Israeli F-35s consistently, they could Intercept drones, Engage cruise missiles, Challenge support aircraft, Force enemy strike packages to be more cautious