It’s not that difficult.
Play around with the scenarios calculator, which I have been using since our last year in the Big 12: https://bball.notnothing.net/bracket_cloud.php?conf=secfb
If Ole Miss, Alabama and Texas win out, Texas is NOT playing in the SEC championship game. Ole Miss and Bama are. Texas can win out but will also need help to make Atlanta. Peter Burns (SEC Network) has also discussed and posted about scenarios.