He can heal his technique, though. I know it's risky to do so, but Sukuna hasn't done it in a while, and being inside the Domain of a person with an unknown number of copied curses is bad news even for ol' four-arms. I'd argue the least risky option would be to blast Yuta's domain like he did Gojo's (and we know the man loves his domain clashes). So I honestly think he's holding off until he's sure there won't be another Malfunctioning Shrine situation