Finally! Thank you for addressing that point. Well, you are free to disagree, bud.
It was not all about it, but it was the single most important contributing factor, IMO.
I thought him starting off the second round with a drastic change in pace looked intentional and not forced by fatigue from the instance I watched it. So please make an argument that pertains to the fight with Usman itself and not to prior signs of fatigue in different fights or wrestling matches.
Also, I thought the flurry he gave at the end showed he still had a good bit left in the tank, which to me indicates that we can't really use tthe fight as a strong indicator of what the limit of his gas tank is at that point of his career. Because there is no real knowing how much more there was still left in the tank, IMO.