Answer
The answer is that Jade Cargill had the longest reign as the AEW TBS Champion. Cargill's reign lasted for 377 days, from January 5, 2022, to January 18, 2023, when she was defeated by Skye Blue. During her reign, Cargill successfully defended her title against a number of challengers, including Red Velvet, Anna Jay, Marina Shafir, and Willow Nightingale.