Instead of having the final star duplicate EMCable items (which at a point where you have stupid amounts of EMC anyways). Instead make it to duplicate a placed block when right clicked and not limit it to EMCable items. That way, you're rewarded for making it to end game.

This of course would need to be a consumable process (meaning one final star to one block copied)

There is a config for that, but it doesnt consume star

Yes, I'm aware of that. Conceptually though, you play through the projectex progression, only to have almost infinite emc and your reward? infinite emc. Why not have something that adds a bit of spice and allow duplication of non-emcable items, but it costs a huge amount of emc; the final star.