Which comic book run features the most complex lex luthor characterization?

Lex Luthor's characterization is most complex in Dan Jurgens' 1990s four-issue miniseries, where the character is portrayed as a calculating genius whose motivations extend beyond simple villainy. The run explores his strategic mind, political maneuvering, and philosophical conflict with Superman, presenting him as both a business tycoon and a morally ambiguous antagonist. While the provided evidence mentions Lex Luthor in 'Batman v Superman: Dawn of Justice,' the comic book run predating and influencing that portrayal is the Jurgens series. Other notable complex portrayals include Geoff Johns' 'New 52' Superman run and 'Action Comics' volumes, but the Jurgens miniseries remains a definitive exploration of Luthor's psyche. Typically, such complexity arises from balancing his role as Superman's intellectual equal with his ideological opposition to alien influence on humanity.