How do Christians who are neither Evolutionists nor Young Earth Creationists explain the timeline of the six days of creation in Genesis chapter 1?

It would appear that ***defining the word ‘day’*** in Genesis ch. 1 has a profound bearing on stances taken. Young Earth Creationists take them to be literal 24-hour-earth-days, but Evolutionists say they must have been millions of years each. The question seems to be boiling down to seeking an explanation from Old Earth Creationists, but I don’t like pigeon-holes, nor do I want to cramp anyone’s style here, if they consider themselves to be Christian, but not an Old Earth Creationist either! ***My second query*** is that if, indeed, the word ‘day’ as used in Genesis has diverse or non-literal meanings, would the elephant in this room be that no time-line is required for believing and understanding the six days of creation? The time factor would not be the point, but could remain unstated because how long it took God to create everything is neither here nor there, from a Christian faith point of view. The universe could have been in process of forming for an unspecified time, so that when planet Earth is first mentioned, its age is simply not known. Nor does its age matter. ***Finally,*** I don’t want anybody to go into whether Christians can rightly claim to be Evolutionists or not; for once I’m prepared to take Stack’s definition of a Christian as the basis for answers – whoever self-identifies as a Christian is to be considered one, when asking or answering.