@Sarcasm But he's still missing part of his soul. That's why he's unable to use his true form with four arms. All fingers are equally strong but he's not complete as long as one of them is still missing. All parts of an engine are equally important but it needs all the parts to orderly functioning. Sukuna can just eat an infinite number of strong sorcerers mummified and go beyond 20 fingers if it's that single.
@1/100000000000 ik he's missing part of his soul but currently he is more stronger than his prime power( as he has 19 finger + corpse equivalent to more than a finger's power). His attack potency is at more than his prime. Gege doesn't wants to show Sukuna getting 20th finger cause he wants to clearly complete who's stronger between prime sukuan and Gojo. Which gojo proved in this chapter.
