Ethical conduct in the form of right speech, right livelihood and right effort are considered to be vital practices leading to enlightenment in Buddhism or Buddhahood.
https://en.wikipedia.org/wiki/Noble_Eightfold_Path
https://studybuddhism.com/en/tibetan-buddhism/about-buddhism/buddha-s-basic-message/a-full-buddhist-life-the-eightfold-path/the-three-trainings
Ethical conduct is also emphasized in the religious philosophies of Hinduism, Jainism and Sufism for attaining enlightenment.
This itself is a refutation of the nihilist and existentialist premise that life is meaningless and all values and virtues are but abstract mental contrivances without any relevance of their own.