The scope of "all" figures in debates over the extent of the atonement. In Rom 5, Paul alternates between "all" and "many". That's striking because those aren't really synonyms. They don't have the same meaning. Yet he's using that terminology as if they have the same meaning.
That's in large part because he's constructing rhetorical parallels, where he compares and contrasts X of something with Y of something else. In that context, I'd say "all" is a way of denoting collectives.
It's like comparing one of something to one of something else, only these are aggregates, so he needs a referring term that indicates a class of individuals.
Collectives needn't include every individual in kind. They can be a representative sample.
But it's necessary in human discourse to be able to refer to groups or make general statements about people, so I think "all" is a linguistic device to make statements of that sort. We need a word for that type of referent. How else would Bible writers be able to talk about collectives, if not to say "all" or "many".
Indeed, in that context, "all" may be a misleading translation. If Paul is using a Greek word to denote collectives, then the English word "all" has the wrong connotations.
This really isn't discussed in commentaries or lexicons, because it's not in the first instance about the meaning of particular words, but something back of that. More about the function of verbal tokens and referring expressions to denote groups or sample groups, collectives, and representative classes. The concept is more philosophical than the meaning a particular word. It's about how to categorize reality. English has a larger vocabulary of specialized terms than Koine Greek to choose from.