If washing isn’t reducing the stickiness, there might be something up with the rice grains themselves (too much of the outer layer removed during processing, long-term storage a dry environment causing cracks, etc.) Lowering the water to rice ratio a bit or steaming really gently after parboiling (like the technique used in this recipe for Iranian chelow) could be enough compensate for the issue, but if all else fails you can always make khichdi or some other kind of porridge.
If washing isn’t reducing the stickiness, there might be something up with the rice grains themselves (too much of the outer layer removed during processing, long-term storage a dry environment causing cracks, etc.) Lowering the water to rice ratio a bit or steaming really gently after parboiling (like the technique used in this recipe for Iranian chelow) could be enough compensate for the issue, but if all else fails you can always make khichdi or some other kind of porridge.