Immortality: My cultivation Has No Bottleneck

Liang Sheng transmigrated into the alternate world, starting off with the talent "Dull Cultivator". A "Dull Cultivator" referred to someone with a sincere heart, unyielding perseverance, and extremely slow cultivation speed. There was no bottleneck in his cultivation.
But what did it matter if there was no bottleneck in his cultivation? Having an extremely slow cultivation speed made everything difficult. However, when he reached the ninth realm of Profound Eternity and broke through to the tenth realm, extending his lifespan by twenty years, he suddenly realized that this was the true meaning of "no bottleneck in cultivation". Any cultivation method could be pushed to its limits and be continuously cultivated.
Since that was the case, if one method of cultivating longevity was not enough, then he would practice ten methods! If ten methods were not enough, then he would practice twenty! In short, he wanted to achieve immortality!