达人 existed classically meaning 'a person who understands life; a sage' (as in the 《论语》 line 己欲达而达人). Around 2000 it was reborrowed via Japanese 達人 ('master of a skill'), and the new sense - an everyday expert - now dominates.
usage
On Douyin, Xiaohongshu, and Taobao, 达人 has become a formal label for recognized influencers in a niche: 美妆达人, 健身达人, 美食达人. The platforms even run 达人 recruitment programs.
