Investors should let Lumen show them where it's headed rather than tell them.Formerly known as telecom company CenturyLink, Lumen Technologies (LUMN 1.03%) has been in the midst of a rebrand and pivot since 2020 amid the artificial intelligence (AI) boom. Like many AI stocks this year, Lumen has put up market-beating returns: It's up 38% through Dec. 22, compared to the S&P 500's gain of 17%.Despite the stock's recent success, let me be the first to say this to prospective investors: Wait until reality matc ...