good and beautiful
頔 centers on a quality of being good and beautiful, likely describing a person's appearance or character in a positive light.
頔 combines 由 with 頁 (head), suggesting a meaning related to the head or appearance. The exact historical development is uncertain.
The left side 由 can suggest a reason or origin, and 頁 is a head. Imagine a person whose head and face are the very picture of goodness and beauty, as if their appearance is the reason for praise.
For テキ, imagine a beautiful person whose good looks are so striking they could be on a tech magazine cover: tech -> テキ, and their beauty is the headline.