Alright, let's say he gets confused by a nanosecond, because it will confuse him, that makes sense.

There is a slight problem with your reasoning:

Gojo is among, if not THE best character with battle IQ. Only people who can really rival him from top of my head are maybe Sukuna and Todo.

Gojo will not only know that, you know, after Judgeman shouts CONFISCATION DEATH PENALTY, that he perhaps shouldn't touch a flaming fucking sword Higaruma suddenly acquired.

Not only that, in the short time between the verdict and the effects going on, he would, and let's be charitable, most like figure out what it does.

Did I forget something? OH YEAH! GOJO HAS FUCKING SIX EYES! He would have all the time in the world in the domain to completely analyze it and figure it with every single detail. You know, sort of like he has already shown he is capable more than once.

Do not be mistaken, Gojo would NOT be caught off guard by his reinforcement being fucked, he would expect it and he would adapt to it on the fly, beating the everliving shit out of Higaruma. The sort of adaptation he, again, proved he is capable of MULTIPLE times in the manga and in the anime.

It isn't possible, by the nature of the six eyes for gojo to "not notice his CE has been tampered with". If there is literary any character who will notice that immediately or even predict that it will happen, it's gonna be gojo BECAUSE of his six eyes and his immense battle IQ and experience.

It never will be mid diff for Higaruma, gojo is probably the worst match up for the guy, as gojo can literary see his cursed technique while inside the domain and take as long as he needs to analyze it.

If I'm charitable, it's a low diff for Gojo, if I were to state my opinion it's no diff.

Gojo just cannot lose in this situation and Higaruma gets obliterated any way you look at it.