I don’t know if you will buy it any more because the Chasam Sofer says it, but here it is on this week’s parsha.
It wasn’t the miracles of the makos that convinced Yisro that Hashem was in charge -- pshita that Hashem could control nature. What convinced Yisro was the pursuit of the Egyptians into Yam Suf and the war waged by Amalek. To think even after seeing all the makos that Bnei Yisrael could be defeated is irrational; it is madness. The behavior of the Egyptians and Amalek could only be explained by the yad Hashem, in the case of the former to destroy them, in the case of the later to punish Bnei Yisrael for relaxing in their dedication to Torah. This power to override the free will of ba’alei bechira and cause them to behave in ways that contradict their own self interest is an even greater miracle than all the makos.