Gojo's CT is more hax'd than Sukuna's (as for black holes, soul manipulation, reality warping), though Sukuna's one has been vastly nerfed for the sake of plot this chapter.
As some ppl said, accepting that Gojo could insta heal his brain from unceasing fatal/lethal slashes with RCT (which has been stated to be impossible, but ok, let's say it's "him"), he should have been able to survive the last attack as he didn't used RCT.
20 fingers Sukuna's in-domain straight slashes in Gojo's head made the same damages than 90% restricted 15 fingers Sukuna did to Yuji lol.
It it wasn't for the plot Gojo should be dead from that last attack, Ryu style.
The "because it's Gojo, dude is that strong" argument is retarded. Even if he's a borned genius with the most hax CT and the 6th eye he doesn't have a superman-like iron body.
So unless Sukuna held back and nerfed himself (which would be BS writting) this part was 100% pure PIS.