From memory there are at least one or two places where “all/everyone” isn’t absolute. e.g. if I said, “all people like chocolate”, as obviously some people don’t like chocolate, the statement must be either hyperbole, or from ignorance, or a lie. However, many of the “all” passages go to great lengths to show the absoluteness of the scope, either by comparison. e.g. if I said, “just as all people sin, so all people are saved” because we know all people sin, the assumption should be that I think all people are also saved. Or by repetition, e.g. if I said, “all people who have lived, all people who are living, and all people who will live, will all lovingly worship God”, there’s a very high chance I really am trying to convey an absolute “all”
However, given “all” is also an adjective, we do need to look at the words it qualifies. For example, obviously when it says “all Jews” that excludes the Gentiles. Of more important to our discussion, when it says “all the elect” I can’t say that this “all” means absolutely everyone, unless I can show you other passages which define “the elect”. The initial assumption would be that “the elect” are a subgroup. But “all” often qualifies words where the initial assumption should be everyone. e.g. “all the world”, “all humanity”, “all people”, “all creation”, etc.