Yes, but the actual transition won't happen until 2023-2025

I remember reading that Texas and Oklahoma are still under contract with the Big XII until the end of the 2024-2025 school year, meaning that their first season in the SEC would be Fall 2025. Of course, it's possible that they could leave sooner, but who knows at this point.

If Cincinnati, et al. do not join the Big XII until after Tx and OK leave, that means that Cincinnati has as many as three more seasons in the AAC. Certainly possible that Kelly could retire at ND before Cincinnati plays a single game as a member of the Big XII conference.