The Perfect Essence Cultivation technique was the most natural technique that could be used to advance to the next Tier.
Dilan's situation may be a little bit unique because he didn't require a faux Divinity to artificially increase his Divine Essence Crystal but the principle was similar.
He absorbed a tremendous amount of Essence from the heaven and earth around him and he used it without any qualms. The Essence in a radius of thousands of kilometers.
Dilan didn't hold back a tiny bit. He was in dire need of Essence so he took it from everywhere without any hesitation.
His advancement was accelerated and Dilan was able to break down the obstacle to the sixth Tier layer by layer. It took him two years in which he didn't move his body by an inch. He didn't eat, drink, sleep, or even think about anything else but the cultivation process of his Divine Essence Crystal.