If anyone knows why the below formula in Formula tool is returning (?=.*\\b\\b) everytime then let me know....I'm just following CHATGPT
IIF(Length(Trim([K1_2]))>0, "(?=.*\\b" + Regex_Replace([K1_2], "([.^$|()\\[\\]{}*+?\\\\])", "\\\\$1") + "\\b)", "")