Many people calculate their Bazi, determine what their Five Elements lack, and only look at the superficial Heavenly Stems and Earthly Branches, but they do not consider the hidden stems, arching, and other factors within the Earthly Branches. If there is a hidden stem in the Earthly Branch, or if an arching branch reveals a Five Element that is missing, then it does not count as lacking that element.

For example, in this Bazi, at first glance, it seems that the Five Elements lack Metal, but in fact, the Earthly Branch Si (Snake) contains a hidden Geng (Yang Metal) stem, so the Bazi does not lack Metal; it can only be said that Metal is weak.
It is more about finding the favorable and unfavorable elements.