The radar on the Kowsar F-5 is too small. It's a light fighter jet. It's only chance is to fly low and maybe use info from AWACS and ground radar stations for its mission.
Aside from that it doesn't have a chance against F-16s or Rafales or even JF-17s in direct confrontations. They will simply see it first and fire first.
Flaws of Kowsar can be rectified with gradual iterations on the design as that happens with any military hardware.
Or extensive redesign while using as much of manufacturing tools as possible.
Greater restriction is Iran not having light weight BVR missiles compared to Fakour-90 / AIM-23B or AIM-54 Phoenix that are over twice as heavy as for example AIM-120.
If Iran develops and mass produces BVR ARH AAM that has weight of 180kg and range of 120km then there is potential to produce a potent subsonic partisan micro fighter jet.
Or at least something like MICA BVR IR that has lock on after launch that can be launched for interception of target to area it is expected to be.
If Iran could improve Jahesh-700 to increase output to 800kg then it is viable to do so.
2300 kilogram empty weight.
4000 kilogram maximum take off weight.
Thrust to Weight ratio at maximum weight is 0.4 that is equivalent to F-5 Tiger II with full afterburner at maximum carrying capacity.
Carry 4 BVR ARH / IR
Ejection Seat 90kg.
Theoretical Jahesh-800 x2 280kg.
Grifo-F equivalent radar 90kg.
These 3 components are 460kg.
1840kg left for rest of empty aircraft.
Fuel capacity of 1000 liters that should be 800kg.
Pilot with equipment should be 100kg in worst case.
That should leave 800kg for payload.