@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.
@DemiGod No, he is not currently strong as he was in his prime. He eat his own fingers and his corpse which was all that was left of him, why would he be stronger than he was in his prime? Why would eating all of himself make him stronger than himself? And the corpse is not worth more than a finger because it does not contain his soul.