Why Cultivate Immortality When You Can Build Rockets?

Looking for a Novel: A Cultivation Story I Read Before.

The female lead transmigrates to a world of immortal cultivation, where she can... rewind time infinitely. People in this world turn into monsters when they reach the Golden Core stage. The female lead has a pure constitution, and her blood can keep those monsters clear-headed. Her blood can also be made into a Heart-Cleansing Pill.