You could use DateTime‘s .diff (doc)
Return the difference between two DateTimes as a Duration.
const date1 = luxon.DateTime.fromISO("2020-09-06T12:00")
const date2 = luxon.DateTime.fromISO("2019-06-10T14:00")
const diff = date1.diff(date2, ["years", "months", "days", "hours"])
console.log(diff.toObject())<script src="https://cdn.jsdelivr.net/npm/luxon@1.25.0/build/global/luxon.min.js"></script>