I just watched this. There may be several storyforms depending on where you focus, but I saw a lot of TEMPTATION at the root of the MC/Travis’ problems throughout the movie. That crumpled $20 bill weighed him down for most of the movie. I saw his thought processes change when he prepared the envelope with the money and reconciling to the reality that he will be dead by the time she gets the note. At that point, he moved forward to accept any and all negative consequences of his action. Also, as a possible hint of the solution the MC was seeking, the movie starts out with MC/Travis describing his driving record as, “Real clean. Like my CONSCIENCE.”
As far as story judgement, I agree he seems like he would go and do it all over again, but he seems content and reconciled to me, so it feels like he is in a good place.