I just finished reading it. Damn that was quite the research and quite a theory. And yeah I think it lines up perfectly.
The separation thing has been mentioned previously I believe.
The interesting part to me is whether Sukuna will remove Yuji and take over the body or whether they will split.
I think the second one might be more likely and that ties into my theory about Megumi and why he needs Megumi to do something for him
And that's this imo. One of these two options.
And it's most likely the first one. Sukuna notices that Megumi's tech involves shadows and ponders about it and calls it much more practical. I think the shadows thing is quite important.