It's hard to give an exact number, but I'd say Itadori has eaten at least 10 Sukuna fingers in the manga. The number keeps fluctuating based on the plot and his encounters with various challenges.
Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.
Not at all. Yuji Itadori's story doesn't end with his execution in the manga. There are many developments and challenges he faces, but execution isn't one of them.
Yuji Itadori survives till the end. The manga doesn't have his death as the final outcome. The story might have thrown challenges at him, but he manages to overcome them and remain alive.