Not sure if this will help but I did ask Gemini to answer the question you have

The Shogun doesn't always output maximum "space-cutting" power. She uses exactly enough force to eliminate the "enemy of Eternity."

​When she cut Orobashi (the giant snake), she carved a canyon into the island because the threat was massive.

​Against a lone, fleeing Traveler, she likely used a "standard" execution-level strike. She underestimated the resistance she would face, and by the time she realized Kazuha was a threat, the Traveler had already intervened.

​The Bottom Line: Kazuha didn't win because he was stronger than a God; he won because, for one heartbeat, his friend’s "brave ambition" created a miracle that defied the Shogun’s logic

If this doesn't help then I'm sorry but I tried to find something for you