Honestly, I don't have the exact number of fingers Itadori has eaten off the top of my head. It depends on the detailed plot developments in the manga. You'd have to go through and carefully follow the story to figure it out accurately.
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.
The Counterattack of Endless Supporting Character was a novel about the counterattack of a supporting character. In this story, you were a supporting character used as a chess piece by the protagonist team and finally achieved your own counterattack.
The question of whether you were eaten or not was a subjective one. In novels, characters usually wouldn't choose to be eaten by others. Instead, they would fight back through their own efforts and wisdom. Therefore, you can decide whether you want to be eaten or not.
No matter what the final result is, you should remain confident and calm, and play to your potential to lay a solid foundation for your counterattack.