Likewise, Gojo would have won domain clash if it was not for a domain without barrier.
All techniques have their pros and cons. Sukuna's is just weaker in terms of dealing with Gojo's infinity.
But Gojo didnt need someone else's technique to counter open barrier domain.
Things should be clear by now: special cursed objects aside, limitless CT very only counter is 10S and nothing else.
There's an obvious parallel between Toji and Sukuna: both are top tier genius fighters who figured out how to bypass limitless and defeat Gojo.
10S is for Sukuna what inverted spear of heaven was for Toji.
My take is that Gege wanted from the very start to show us what would have been a fight between prime Toji and prime Gojo if Toji had the 10S CT, and he used Sukuna to showcase it.
By the end, Gojo's entire plot in JJK was him fighting Zenin clan members, both families being somehow linked by a cursed fate.
In other words, and ironically enough, Megumi isn't Sukuna's vessel but rather the opposite: Gege used Sukuna as a vessel for the Zenin CT.
It has never been Satoru vs Sukuna, but Gojo clan vs Zenin clan at their peak.