He's still a curse though... being sealed inside a cursed object literally and is being held inside a Human vessel now. Whether he could do it as a human or not isnt confirmed yet but im willing to give him the benefit of the doubt.
Good point but too much of going around for me to give it to him too just yet. Ill wait till we get some form of canon confirmation that he could do so.
Well I think I should clarify the misconception that it's easier for curses to use RCT. They actually can't use RCT at all. RCT is the process of turning negative cursed energy into positive energy, and we all know when exposed to pure positive CE curses literally explode/are instantly exorcised. So if a curse could produce positive energy and then used it on themselves it'd actually kill them instead of healing them. What curses are actually capable of doing is just using straight up negative CE to heal. Which is why is not as impressive as RCT, because RCT is one of the most difficult maneuvers in the series.
Also it's explicitly confirmed in the fanbook that Sukuna used RCT to literally REVIVE YUJI FROM THE DEAD WHILE HIS SOUL WAS STILL INSIDE YUJIS BODY. His RCT is on an entirely different level than any other character we've seen so far.
Totally fair to want more evidence for the Kenjaku point though.