Jujutsu Kaisen: spoilers:end of spoilers
Okay, so the soul swapping is an aspect of Ui Ui's CT instead of an application of what Yuji learned about souls. And he's apparently soul-swapped and trained with more than just Kusakabe, so Yuji likely has several CTs aside from what he gained from eating his brothers. Meanwhile, Sukuna opens with Malevolent Shrine (which looks like it's fused with Megumi's Innate Domain), and uses the same wide-scaled assault that he used in Shibuya. Yuji is able to tank it with only the loss of a foot (which he immediately regenerated), but Sukuna then prepares to use Furnace (Yay, we finally know the actual name of his fire CT) to finish him off.