This story is about a man from our world who finds himself in the body of a miner in a Xianxia world. He doesn't have much money, nor does he have any cultivation. He has no special talent either, so no sect accepted him. Instead, he spends his days mining, fishing, and doing odd jobs for a living while training his body and playing around with the minute amount of ki he has.
A year passes, and he notices that his ki has grown. He can even move it much easier now. Deciding to test a theory, he increases his daily workouts to extremes and adds meditation sessions before sleep.
The results show themselves, as not even six months later he can now sense other people's ki, though not as clearly and not that far either. But the important part is that he can RUN. His speed now matches highway speeds, and he has the strength of ten men. It is nothing compared to other cultivators, but he didn't need any special technique to get this strong. So why are all cultivators using some complicated method?
What the self-insert didn't know was that while his method is indeed much faster, it also required an immense amount of time training one's body and one's mind, as well as an increased amount of food as his body began to require more energy to keep functioning. He will only have his life increased by a few decades unless he reaches divinity, which is when he can continuously be at full power while keeping his ki within his body, preventing it from leaking out and being detected by those who aren't divine.
The secret methods regular cultivators use basically convert their bodies into divine beings. With every breakthrough, they increase their divinity, starting with a fraction of a fraction. This increases the cultivator's life and decreases their need for food until they become immortal by reaching full divinity.