What killed Cody in AEW - and that speaks to the extremely permissive management & booking team (hey, those are one and the same!) - was that he couldn't challenge for the top belt MONTHS into the company's life. Killed any chance he had of overcoming a booking slump.
He still did elevate some young talent to that next level, like Sammy and Darby, but he never could have that top reign, and instead was doing feuds that didn't really mesh with the rest of the show. The Codyverse, if ya wheel.