Christians have always had a wide variety of beliefs about the afterlife, and just about everyone (who chooses) is able to find biblical support for their views. The Bible itself has an enormous range of views.
Among other things, there have always been Christians who have thought that there must be varying levels of punishment for sinners in the afterlife. The guy on the street who does his best but is not always a very good father surely doesn’t get punished to the same degree as Hitler.
Among believers who are convinced that there are different levels of punishment I would certainly class those who believe in purgatory. Even though it is a view almost universally rejected by Protestants, purgatory can make a lot of sense even to some of them. The afterlife is not just black and white, one thing or the other, either/or – it is not either eternal bliss for all the saints and eternal torment for all the sinners. There must be gradations, right?
And purgatory is a way of implementing the gradations. Only a few people go straight to their heavenly glory. Those are the true saints, for example, the martyrs who are tortured and killed for standing up for their faith. The rest of the saved have to pay a price for their transgressions and unfaithful behavior. Purgatory is a way to imagine how that happens.
One passage that can be appealed to in support of some such view is