About the only way I have been able to improve these horrible kit gun triggers, is to remove the existing trigger, from the trigger plate, and fabricate a new trigger that is tall enough to place the pivot pin higher in the stock ( pin it right through wood, behind the side plate) . By relocating the trigger pivot, and sear contact point, in regards to the sear bar, the sear can be moved closer to the trigger pivot, you now have the mechanical advantage going the right way. So now it is working to make the felt trigger pull much less.
A primitive trigger is easily made of hot rolled 1/8th"X 1" mild steel, and can be forged cold.
Hungry Horse