John was one of the last written, but it covers the same period of time as the other gospels. That’s what I meant by chronological. The text itself, not authorship. I don’t think an ordering in authorship time is any more sensible, particularly given the probable presence of forgeries and the undateableness of most of them.

Luke and Acts were probably not part of the same document, but were written separately. The beginning of Acts supports this when the author speaks of his previous book and re-addresses his audience. I suppose you could argue it’s all an interpolation, but the books were separate before the canon was established.

Either way, I wouldn’t consider it arbitrary to have all the gospel narratives together and then have subsequent events afterward. Perhaps you could argue that Luke and John should be swapped, so as to proceed from Luke to Acts, but then Luke is much more like Matthew and Mark theologically and stylistically. You could set John first, but it’s the most difficult of the four. It’s hard to see how your example is a good one of arbitrary ordering. Four books covering the same material are all in one place; the three synoptic gospels are in the same place - how else would you do it?