First take a glance at the multifaceted corruptive flesh-system on its own. You have unbelievers who are more noble-minded when it comes to the Gospel (like the Bereans) then you’d have others who are outright enemies of righteousness (Saducees). You have some that are very zealous for God but not according to knowledge (like many of the Pharisaic Jews) and some that are zealously sinful but by ignorance (like Paul). Then you have others who say they can see but are blind (the group in John 9) and yet others who take a wait and see approach (like Gamaliel). All of these are rightfully merely human souls. They are acting of their own wide range of wisdom, according to God’s common grace, but all are naturally fallen and thus utterly lost in their foolishness.
Neither is more fallen than the other. Neither is more mature in their falleness than the other. Sure, some of their sins are more numerable and heinous than the other—so that some who are saved will say that there was much forgiven—but none of them, by their mere activity, pop into the Church as Christians by Self-Action.
Second, note how good the assembly at Corinth looked: