A common criticism of Christianity is that it is too limited in time and space for its claims to be true: Christianity has only been around for a relatively short period of humanity's existence, and has only been prevalent in certain parts of the world. Most people could never have become Christians as they never encountered Christian teachings - so why would being a Christian as established later in history be required for salvation (i.e. Heaven), assuming that God is just?
Intuitively, this argument makes a lot of sense: if most people in history lived without any notion of Christian teachings and Christian God, why would the latter require belief and a certain way of life for people to be be allowed to live in an afterlife they had no knowledge of in the first place? One possible counterargument could be that historical Christian teachings are only to orient and assist people, who are otherwise meant to come to similar (Christian-like) conclusions regarding normative morality on their own. This reasoning, of course, is not without problems as it renders the specifics of Christianity irrelevant and reduces it to the level or mere practical morality. Another possible counterargument is that the interpretation of Christianity assumed in the question is wrong, and that e.g. God can be just while those who are not Christians (for whatever reason) cannot be saved - the problem then becomes about the notion of justice as attributed to God.
Does the problem have a common name in philosophy? Has it been addressed more rigorously by philosophers, particularly from the Christian apologetics perspective? Are there common counterarguments? If so, are they specifically Christian, or could they be used to defend other religions? I'm particularly interested in the work of modern and contemporary philosophers, as well as theoretical analyses of implications of the potential resolutions.