Starting at 2nd OT a 2 pt attempt is required and in the 3rd OT team only attempt a 2pt conversion, no more starting at the 25 in 3rd OT
“Also, if the game reaches a third overtime, teams will run alternating 2-point plays, instead of starting another drive at the opponent's 25-yard line. This is a change from the previous rule, which started to use 2-point plays in the fifth overtime period.”
That’s how the Utah SDSU game ended 33-31 after the 3rd OT.
Unlikely but not impossible