Having to farm 900 stability to target farm an extremely rare loot from a boss is a chore worse than diablo 4. It is too many stability.
So please do one of the following or all of them:
Lower the amount necessary.
Increase the amount you get per node. (The base amount, because it is extremely inefficient to farm all the bonus. Or increase the mob density and the amount of bonus they give)
Buff the drop chance from boss specific uniques.
Anything above 400 is just too much.