How does one get absolutely jacked like Usak and Taeheon? [serious]

Their physiques are very inspiring. Usak obviously has had to make sacrifices like the chicken smoothie instead of eating freely. Between s1 and s2, Taeheon seems to have grown lots of muscle and cut fat as well.

Besides exercising for gains, what is more possible in Asia that allows for such progress? Gyms seem expensive in Asia so having money and time plus discipline to exercise certainly helps but public transit access is ubiquitous as well compared to having to drive to a gym. I can't say I know much about supplements or other enhancements.

Two call outs:

• Nutrition Mindfulness: I understand there's been a lot of trending attention towards increasing protein intake for fitness. I'm aware of increasing rates of colon cancer amongst youths so fiber intake would also be valued.
• Function + Form Goals: Personally I also care about flexibility and functional fitness, not just aesthetics. I wouldn't want to gain muscle and then not be able to touch my shoulders, which I've seen happen to some lifters who overindex on arms, for example.

Would love to hear people's thoughts!